Analytical Procedures and Quality Assurance for … · Analytical Procedures and Quality Assurance for Geothermal Water Chemistry ... Procedure ... STANDARDIZATION OF SILVER NITRATE

Analytical Procedures and Quality

Assurance for Geothermal Water Chemistry

Pang Zhong-he and Halldór Ármannsson

Editors

United Nations University

Geothermal Training Programme

2005

PREFACE

Chemical analyses of geothermal fluids need special attention compared to normal

freshwater samples mainly due to the fact that they are often highly saline, with total

dissolved solids up to tens of grams per litre. In addition to this, they often contain boric

acid and other weak acids and therefore may introduce a matrix effect that can be a cause

of unreliable analytical results for HCO3, for example. Furthermore, it has been realized

that different procedures are being used in different laboratories for the same

constituents, for example, silica concentration, which is a key parameter in geothermal

investigations as an ideal geothermometer. Standard procedures should be used for

analysis in order to ensure comparability of results.

Based on the results of several rounds of inter-laboratory comparison exercises sponsored

by the International Atomic Energy Agency (IAEA) in the past several years, it has been

realized that quality is still an issue to be addressed in geothermal chemical analysis.

Inter-laboratory comparison exercises, in addition to routine caution in the laboratory,

have proven to be effective means of analytical quality assurance based on experience

from the implementation of such exercises.

Water chemistry data is essential information required for the characterization of

geothermal fluids and evaluation of energy potential of geothermal fields by

geothermometry, and provides good indicators for monitoring reservoir changes in

response to production. Analytical results with good quality are the key to accurately

evaluating geothermal resources and effectively solving reservoir management problems.

As a consequence, at a project planning meeting organized by the IAEA in July 2000 in

Morelia, Mexico, geothermal experts from Costa Rica, El Salvador, Guatemala,

Indonesia, Philippines, Mexico and Nicaragua suggested a “cookbook” type of document

be compiled and distributed to facilitate information exchange and to support training and

routine performance of geothermal chemistry laboratories working on geothermal water

samples to achieve improved analytical quality. The document should include standard

procedures used by experienced geothermal chemistry laboratories and quality assurance

measures.

The 15 chemical constituents covered in this document coincide with the inter-laboratory

comparison exercises organized by the IAEA with 42 methods of analysis for the

constituents commonly analyzed for in geothermal water described. Besides 3 methods of

standardization of commonly used reagents are presented. The presentation of each

method has been standardized under the following headings: Scope (basis for the method,

detection limit, possible interferences and ways of combatting them); References;

Materials and equipment; Reagents (incl. descriptions of preparation); Procedure;

Calculations; and Quality assurance/quality control. In the appendices, a report of an

inter-laboratory comparison exercise, undertaken in 2003, is included just to show an

example of the typical evaluation procedure of results and assessment of performance of

individual laboratories.

We would like to thank authors from the twelve laboratories that have prepared writeups

of their adopted procedures. The efforts of Dr. Rosa Maria Barragan and Ms. Rowena A.

Isidro who reviewed the original manuscripts are acknowledged. We also thank the

United Nations University (UNU) Geothermal Training Programme for its interest in

publishing the book and we do hope that this publication will serve as a valuable aid to

the UNU fellows that do chemistry work and in general to laboratory personnels dealing

with geothermal water chemistry.

The editors

28 April, 2006

Beijing and Reykjavik

TABLE OF CONTENTS

PREFACE ................................................................................................................................... 3

PROCEDURES ............................................................................................................... 15

ALUMINIUM (FLUORIMETRIC WITH LUMOGALLION) ...................................... 15

Scope ............................................................................................................... 15

References ......................................................................................................... 15

Materials and Equipment .................................................................................. 15

Reagents and Standards ..................................................................................... 15

Procedure ........................................................................................................... 16

Calculation ........................................................................................................ 16

Quality Assurance/Quality Control ................................................................... 17

AMMONIA (SPECTROPHOTOMETRIC WITH INDOPHENOL BLUE) .................. 18

Scope ............................................................................................................... 18

References ......................................................................................................... 18



Procedure ........................................................................................................... 19

Calculation ........................................................................................................ 20


AMMONIA (ION SELECTIVE ELECTRODE) ............................................................ 21

Scope ............................................................................................................... 21

References ......................................................................................................... 21



Procedure ........................................................................................................... 22

Calculation ........................................................................................................ 22


AMMONIA (NH3-N) (SPECTROHOTOMETRIC WITH NESSLER

REAGENT) ....................................................................................................... 24

Scope ............................................................................................................... 24

References ......................................................................................................... 24

Materials and equipment ................................................................................... 24

Reagents and standards ..................................................................................... 24

Procedure ........................................................................................................... 25

Calculation ........................................................................................................ 26


BICARBONATE, CARBONATE AND TOTAL CARBON DIOXIDE

(TITRIMETRIC) ............................................................................................... 27

Scope ............................................................................................................... 27

References ......................................................................................................... 27



Procedure ........................................................................................................... 28

Calculations ....................................................................................................... 30


BORON (TITRIMETRIC WITH MANNITOL) ............................................................ 31

Scope ............................................................................................................... 31

Reference ........................................................................................................... 31



Procedure ........................................................................................................... 31

Calculation ........................................................................................................ 32


BORON (ICP-ATOMIC EMISSION SPECTROMETRY) ............................................ 33

Scope ............................................................................................................... 33

References ......................................................................................................... 33



Procedure ........................................................................................................... 34

Calculation ........................................................................................................ 35


BORON (ICP-MASS SPECTROMETRY) .................................................................... 37

Scope ............................................................................................................... 37

References ......................................................................................................... 37



Procedure ........................................................................................................... 38

Calculation ........................................................................................................ 39

Quality Assurance / Quality Control ................................................................. 39

BORON (SPECTROPHOTOMETRIC WITH CARMINE)........................................... 41

Scope ............................................................................................................... 41

Reference ........................................................................................................... 41



Procedure ........................................................................................................... 41

Calculation ........................................................................................................ 42


BORON (SPECTROPHOTOMETRIC WITH CURCUMIN) ....................................... 44

Scope ............................................................................................................... 44

References ......................................................................................................... 44



Procedure ........................................................................................................... 45

Calculation ........................................................................................................ 45

Quality Assurance/Quality control .................................................................... 46

BORON (SPECTROPHOTOMETRIC WITH AZOMETHINE-H)............................... 47

Scope ............................................................................................................... 47

References ......................................................................................................... 47



Procedure ........................................................................................................... 48

Calculation ........................................................................................................ 48


BORON (ATOMIC ABSORPTION SPECTROPHOTOMETRY) ................................ 50

Scope ............................................................................................................... 50

References ......................................................................................................... 50



Procedure ........................................................................................................... 51

Calculations ....................................................................................................... 52

Quality Assurance/Quality control .................................................................... 52

CALCIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY) ........................... 53

Scope ............................................................................................................... 53

References ......................................................................................................... 53



Procedure ........................................................................................................... 54

Calculation ........................................................................................................ 54


CALCIUM (ICP-ATOMIC EMISSION SPECTROMETRY) ....................................... 56

Scope ............................................................................................................... 56

References ......................................................................................................... 56



Procedure ........................................................................................................... 57

Calculation ........................................................................................................ 58


CALCIUM (TITRIMETRIC WITH EDTA)................................................................... 59

Scope ............................................................................................................... 59

Reference ........................................................................................................... 59



Procedure ........................................................................................................... 60

Calculation ........................................................................................................ 61

Quality Assurance/Quality control. ................................................................... 62

CALCIUM (ION CHROMATOGRAPHY).................................................................... 63

Scope ............................................................................................................... 63

References ......................................................................................................... 63



Procedure ........................................................................................................... 64

Calculation ........................................................................................................ 65


CHLORIDE (ARGENTOMETRIC TITRATION) ......................................................... 67

Scope ............................................................................................................... 67

References ......................................................................................................... 67



Procedure ........................................................................................................... 68

Calculation ........................................................................................................ 69


CHLORIDE (POTENTIOMETRIC TITRATION) ........................................................ 70

Scope ............................................................................................................... 70

Reference ........................................................................................................... 70



Procedure ........................................................................................................... 71

Calculation ........................................................................................................ 71


CHLORIDE (SPECTROPHOTOMETRIC WITH THIOCYANATE) .......................... 73

Scope ............................................................................................................... 73

Reference ........................................................................................................... 73



Procedure ........................................................................................................... 74

Calculation ........................................................................................................ 74


CHLORIDE (ION CHROMATOGRAPHY) .................................................................. 75

Scope ............................................................................................................... 75

References ......................................................................................................... 75



Procedure ........................................................................................................... 77

Calculation ........................................................................................................ 78


FLUORIDE (ION SELECTIVE ELECTRODE-ISE) ..................................................... 80

Scope ............................................................................................................... 80

References ......................................................................................................... 80



Procedure ........................................................................................................... 81

Calculation ........................................................................................................ 81


FLUORIDE (ION CHROMATOGRAPHY) .................................................................. 83

Scope ............................................................................................................... 83

References ......................................................................................................... 83



Procedure ........................................................................................................... 84

Calculation ........................................................................................................ 84


FLUORIDE (SPADNS SPECTROPHOTOMETRIC) ................................................... 86

Scope ............................................................................................................... 86

References ......................................................................................................... 86



Procedure ........................................................................................................... 87

Calculation ........................................................................................................ 88

Quality Assurance/ Quality Control .................................................................. 88

IRON (SPECTROPHOTOMETRIC WITH TPTZ) ........................................................ 90

Scope ............................................................................................................... 90

References ......................................................................................................... 90



Procedure ........................................................................................................... 91

Calculation ........................................................................................................ 91


LITHIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY) ............................. 93

Scope ............................................................................................................... 93

References ......................................................................................................... 93



Procedure ........................................................................................................... 94

Calculation ........................................................................................................ 94


MAGNESIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY) ..................... 96

Scope ............................................................................................................... 96

References ......................................................................................................... 96



Procedure ........................................................................................................... 97

Calculation ........................................................................................................ 97


MAGNESIUM (ION CHROMATOGRAPHY) ............................................................. 99

Scope ............................................................................................................... 99

Reference ........................................................................................................... 99

Material and Equipment .................................................................................... 99


Procedure ......................................................................................................... 100

Calculation ...................................................................................................... 100

Quality Assurance / Quality Control ............................................................... 100

PH (ELECTROMETRIC) ............................................................................................. 101

Scope ............................................................................................................. 101

Reference ......................................................................................................... 101

Materials and Equipment ................................................................................ 101

Reagents and Standards ................................................................................... 101

Procedure ......................................................................................................... 101

Quality Assurance/Quality Control ................................................................. 102

POTASSIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY) ..................... 103

Scope ............................................................................................................. 103

References ....................................................................................................... 103



Procedure ......................................................................................................... 104

Calculation ...................................................................................................... 104


POTASSIUM (ION CHROMATOGRAPHY) ............................................................. 106

Scope ............................................................................................................. 106

Reference ......................................................................................................... 106



Procedure ......................................................................................................... 107

Calculation ...................................................................................................... 107


POTASSIUM (ATOMIC EMISSION SPECTROSCOPY (AES) ................................ 108

Scope ............................................................................................................. 108

References ....................................................................................................... 108



Procedure ......................................................................................................... 109

Calculation ...................................................................................................... 109

Quality Assurance/Quality control .................................................................. 109

SILICA-TOTAL (SPECTROPHOTOMETRIC WITH AMMONIUM-

MOLYBDATE) .............................................................................................. 110

Scope ............................................................................................................. 110

References ....................................................................................................... 110



Procedure ......................................................................................................... 111

Calculation ...................................................................................................... 112


SILICA (SPECTROPHOTOMETRIC WITH AMMONIUMMOLYBDATE

AND HETEROPOLY BLUE) ........................................................................ 113

Scope ............................................................................................................. 113

References ....................................................................................................... 113


Procedure ......................................................................................................... 114

Calculation ...................................................................................................... 114


SILICA (ATOMIC ABSORPTION SPECTROPHOTOMETRY) ............................... 116

Scope ............................................................................................................. 116

References ....................................................................................................... 116



Procedure ......................................................................................................... 117

Calculations ..................................................................................................... 118

Quality control ................................................................................................. 118

SILICA, TOTAL (ICP– ATOMIC EMISSION SPECTROMETRY) .......................... 120

Scope ............................................................................................................. 120

References ....................................................................................................... 120



Procedure ......................................................................................................... 121

Calculation ...................................................................................................... 121


SODIUM AND POTASSIUM (ICP-ATOMIC EMISSION

SPECTROMETRY) ........................................................................................ 122

Scope ............................................................................................................. 122

References ....................................................................................................... 122



Procedure ......................................................................................................... 123

Calculation ...................................................................................................... 124


SODIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY) ............................ 125

Scope ............................................................................................................. 125

References ....................................................................................................... 125



Procedure ......................................................................................................... 126

Calculation ...................................................................................................... 126


SODIUM (ION CHROMATOGRAPHY) .................................................................... 128

Scope ............................................................................................................. 128

Reference ......................................................................................................... 128



Procedure ......................................................................................................... 129

Calculation ...................................................................................................... 129


SODIUM (ATOMIC EMISSION SPECTROSCOPY (AES) ....................................... 130

Scope ............................................................................................................. 130

References ....................................................................................................... 130



Procedure ......................................................................................................... 131

Calculation ...................................................................................................... 131

Quality Assurance/Quality control .................................................................. 131

SULFATE (INDIRECT SPECTROPHOTOMETRIC WITH BARIUM

CHROMATE AND BROMOPHENOL BLUE) ............................................. 132

Scope ............................................................................................................. 132

Reference ......................................................................................................... 132



Procedure ......................................................................................................... 133

Calculation ...................................................................................................... 133


SULFATE (ION CHROMATOGRAPHY) .................................................................. 135

Scope ............................................................................................................. 135

References ....................................................................................................... 135



Procedure ......................................................................................................... 136

Calculation ...................................................................................................... 137


SULFATE (TURBIDOMETRIC) ................................................................................. 139

Scope ............................................................................................................. 139

References ....................................................................................................... 139



Procedure ......................................................................................................... 140

Calculation ...................................................................................................... 140


STANDARDIZATION OF NAOH AGAINST KHP ................................................... 141


Reagents .......................................................................................................... 141

Procedure ......................................................................................................... 141

Calculation ...................................................................................................... 141

STANDARDIZATION OF HCL AGAINST NAOH ................................................... 143


Reagents .......................................................................................................... 143

Procedure ......................................................................................................... 143

Calculation ...................................................................................................... 143

STANDARDIZATION OF SILVER NITRATE AGAINST SODIUM

CHLORIDE ..................................................................................................... 145


Reagents .......................................................................................................... 145

Procedure ......................................................................................................... 145

Calculation ...................................................................................................... 145

BIBLIOGRAPHY ................................................................................................................... 146

APPENDIX I. ABBREVIATIONS ........................................................................................ 150

APPENDIX II. LIST OF CONTRIBUTING LABORATORIES BY METHODS ............... 151

APPENDIX III. CONTACT INFORMATION OF THE CONTRIBUTIING

LABORATORIES ......................................................................................................... 154

APPENDIX IV. LIST OF PERSONS INVOLVED IN DRAFTING AND REVIEW

OF THE DOCUMENT.................................................................................................. 156

APPENDIX V: IMPROVING ANALYTICAL QUALITY OF WATER

CHEMISTRY THROUGH INTER-LABORATORY COMPARISON ....................... 157

APPENDIX VI: 2003 INTER-LABORATORY COMPARISON OF

GEOTHERMAL WATER CHEMISTRY .................................................................... 166

INTRODUCTION ......................................................................................................... 168

METHODOLOGY ........................................................................................................ 169

Collection and Preparation of Samples ......................................................................... 169

Evaluation of Results ..................................................................................................... 170

Homogeneity ................................................................................................... 170

Stability ........................................................................................................... 170

Results of all labs ............................................................................................ 171

DISCUSSSION OF RESULTS ..................................................................................... 172

GW-03-01 Mixed Natural and Synthetic Brine ............................................................. 173

GW-03-02 Natural Brine ............................................................................................... 174

GW-03-03 Synthetic Brine ............................................................................................ 174

Laboratory Performance in Inter-laboratory Comparison ............................................. 174

CONCLUSIONS AND RECOMMENDATIONS ........................................................ 175

REFERENCES .............................................................................................................. 176

LIST OF TABLES, FIGURES AND ANNEXES ........................................................ 177

1. COUNTRY .................................................................................................................... 217

2. NAME/ADDRESS OF LABORATORY...................................................................... 217

3. COUNTRY .................................................................................................................... 219

NAME/ADDRESS OF LABORATORY ............................................................................... 219

4. COUNTRY .................................................................................................................... 220


6. COUNTRY .................................................................................................................... 222


8. COUNTRY .................................................................................................................... 223


10. COUNTRY .................................................................................................................... 225


12. COUNTRY .................................................................................................................... 227


PROCEDURES

ALUMINIUM (FLUORIMETRIC WITH LUMOGALLION)

Iceland GeoSurvey, Iceland

Scope

The method is applicable to acidified water samples at concentrations ≥ 0.05 g/l but if

the concentration exceeds 50 g/l dilution is needed

Al forms a fluorescent complex with lumogallion at pH = 5. Glassware may interfere

with the reaction and plastic apparatus is preferred.

Iron interferes at concentrations > 200 g/l but this can usually be avoided by dilution.

Organic matter may also interfere but this can be overcome by irradiation with UV light

References

Hydes, D.J. and Liss, P.S. (1976); Vitense, K.R. and McGown, L.B. (1987).

Materials and Equipment

Plastic reagent bottles, 100 ml

Plastic volumetric flasks, 25, 50, 100 and 250 ml

Plastic measuring cylinders, 50 ml

Pipettes, 0.5 – 2 ml

Plastic film.

pH meter

Fluorimeter with filters or monochromator

Reagents and Standards

Buffer solution. Dissolve 45 g of sodium acetate (CH3COONa.3H2O) in demonized

water, add 6.5 ml glacial acetic acid and dilute to 100 ml. Check that this will buffer 50

ml of acidified water (1 ml conc. HNO3 + 499 ml water) plus 1 ml ammonia solution to

pH = 5.0 ± 0.1. Adjust with acetic acid if needed.

Ammonia solution, 25%.

Lumogallion solution. Dissolve 0.02 g of lumogallion in demonized water and dilute to

100 ml

Aluminum stock solution. 1 g Al/l

Aluminum working solutions. 1-4 g/l made up daily from the stock solution

Procedure

If dilution is required add 10 to 50 ml sample of acidified water sample (1 ml conc.

HNO3 + 499 ml water) and dilute with similarly acidified deionized water to 250 ml.

Using a 50 ml measuring cylinder transfer 5 portions of undiluted or diluted sample to

clean 100 ml polypropylene bottles and add reagents as specified in the following table.

Before adding the lumogallion check that the pH of the solution is 5.0 ± 0.1. If not adjust

with acetic acid or ammonia. Prepare reagent blanks with 50 ml acidified deionized

water, 1 ml ammonia, 0.5 ml buffer and 0.5 ml lumogallion.

Reagents to be added

Bottle

No.

Ammonia

Ml

Buffer

ml

Al amount

ml, g

Lumogallion

Ml

1 1 0.5 0 0

2 1 0.5 0 0.5

3 1 0.5 1.0 0.5

4 1 0.5 1.5 0.5

5 1 0.5 2.0 0.5

Cover the bottles with plastic film

Heat in a water bath at 70-80°C for 1 hour to ensure complete complexing of the

lumogallion. Cool the bottles to room temperature

Measure the fluorescence of the solution in each bottle using the 505 nm excitation

wavelength and the 565 nm emission wavelength, heating the lamp for at least 30

minutes before starting measurements. The solution in bottle No. 1 should show zero

fluorescence unless the sample fluoresces naturally in which case the natural fluorescence

should be subtracted from the measured fluorescence in the solutions from bottles No. 2-

5.

Calculation

Prepare a calibration curve for each sample and added standard. (See Figure). The

fluorescence of the solution from bottle No. 2 minus that of the reagent blank gives the

fluorescence due to the sample and hence the aluminum concentration. If the sample was

diluted multiply with the dilution factor to obtain the total concentration.

g

Calibration curve for aluminum determination

Quality Assurance/Quality Control

Analyze control samples and standards prior to analysis of samples.

Check that the fluorescence of the sample (bottle No. 2) is at least 8 times that of the

reagent blank, otherwise reproduction is likely to be poor. Try a new batch of reagents to

improve the reagent blank.

If the plot is not linear use a smaller sample volume.

Standard concentrations should bracket the sample concentrations and should be within

the working range.

Analyze one set of duplicate samples for every five samples (or with each batch of

samples, whichever is less). Acceptance limits for duplicate samples is 5%.

To one sample out of every ten samples (or with each batch of samples, whichever is

less) add a known amount of the analyte and reanalyze to confirm recovery. Recovery of

the added aluminum should be between 95 and 105%. Otherwise, reanalyze the whole

batch.

AMMONIA (SPECTROPHOTOMETRIC WITH INDOPHENOL BLUE)


Scope

Ammonia reacts with hypochlorite at pH 8 - 11.5 to form monochloramine, which with

phenol, a catalytic amount of nitroprusside and excess hypochlorite, gives indophenol

blue. The precipitation of Mg and Ca ions is prevented by complexation with citrate. A

reaction temperature of 37 - 40oC causes complete color formation within 30 minutes.

The method is applicable to the determination of ammonia (NH3) in water with

concentrations ranging from 0.007 mg/l NH3 (using a 10 cm cell) and above. Higher

concentrations than about 1 mg/L can be determined following appropriate dilutions.

The sum of ammonium and ammonia is determined.

Mercuric ions at 2-40 mg/l decrease the indophenol blue by about 20% and samples

containing more than 2 mg/l sulphide should be diluted.

References

Koroleff, F. (1983)


Amber glass bottles, 1000 ml and 100 ml

Glass bottle, 100 ml

Polyethylene bottle, 500 ml

Volumetric flasks, 100 ml and 50 ml (several)

Pipettes, 0.5, 1, 3, 5 ml

Erlenmeyer flasks, 100 ml

Burette, 25 ml

pH meter

UV-Visible Spectrophotometer with appropriate size sample cells (1-10 cm)


Ammonia stock solution, 100 ppm: Dry ammonium chloride at 100°C. Dissolve 31.7 mg

in freshly deionized water and dilute to 100 ml. Preserve with a drop of chloroform and

store in a glass bottle in a refrigerator.

Ammonia intermediate standard solution: Dilute the stock solution 20 times with freshly

deionized water to give a 5-ppm ammonia solution daily.

Phenol reagent: Dissolve 80 g phenol in 200 ml ethanol and add 600 ml freshly deionized

water. Dissolve 600 mg disodium nitroprusside dehydrate in 100 ml freshly deionized

water and add to the phenol solution. Store the reagent in a tightly stoppered amber bottle

in a refrigerator.

Tri-sodium citrate solution: Dissolve 240 g tri-sodium citrate dehydrates in about 500 ml

freshly deionized water. Dissolve 40 g sodium hydroxide in freshly deionized water and

dilute to 1 l to make a 1 N sodium hydroxide solution. Make the tri-sodium citrate

solution alkaline with about 10 ml of the sodium hydroxide solution. Add anti-bumping

granules and remove ammonia by boiling until the volume is below 500 ml. Cool and

dilute to 500 ml with freshly deionized water. Store in a well stoppered polyethylene

bottle.

Hypochlorite reagent: Add 2 ml phenol reagent and 1 ml tri-sodium citrate solution to 50

ml freshly deionized water. Titrate to a pH of 11 with 1 N sodium hydroxide (prepared

for the preparation of the tri-sodium citrate solution) using a pH-meter. Use the result to

dilute the sodium hydroxide solution in such a way that a pH of 11 would be obtained by

adding 2 ml of it to the phenol tri-sodium citrate solution. Dissolve 0.5 g

dichloroisocyanuric acid in 100 ml of this diluted sodium hydroxide solution and store in

an amber glass bottle in a refrigerator.

Procedure

Half fill 50 ml volumetric flasks, due to hold blank, standards and samples with freshly

deionized water.

Add 1, 3 and 5 ml aliquots of intermediate standard solution to three of the flasks to make

up 0.1, 0.3 and 0.5 ppm standards, and 0.5 ml ones of samples drawn from gas sampling

tubes immediately upon opening, to the flasks intended for them.

Empty the contents of the volumetric flasks into 100 ml Erlenmeyer flasks.

Add 2 ml phenol reagent and swirl well.

Add 1 ml tri-sodium citrate solution and swirl.

Add 2 ml hypochlorite reagent and swirl well.

Stopper the Erlenmeyer flasks and place them in a thermostatic water bath at 37 – 40°C

for 30 minutes.

Take the flasks out of the water bath and leave to cool for 30 minutes.

Measure the absorbance of blank, standards and samples at 630 nm within 24 hours of

color development.

Calculation

Read ammonia concentration in mg/l directly from the instrument or prepare standard

calibration curve to interpolate the sample concentration.

For diluted samples, calculate the final concentration using:

mg/l NH3 = concentration x dilution factor


All samples should be collected into gas sampling tubes and analyzed immediately upon

their opening

Since ammonia pervades the atmosphere care should be taken that only freshly deionized

water is used at all stages and that all reagent bottles are kept tightly stoppered.

A reaction pH higher than 11 must be avoided due to erratic blank values with greenish

shades.

The chemicals used in this method are dangerous so that their preparation and the

execution of the procedure should take place in a fume cupboard or in the open air if this

is not available.

Analyze reagent blank, check standard and control sample/standard after every five (5)

samples, or with each batch of samples, whichever is less. The check standard is chosen

from one of the calibration standards, while the control standard/sample is a separate

preparation. The determined value should be within 5% of the known or expected

concentration. Otherwise, all samples in the batch should be reanalyzed.


the working range.



To one sample out of every five (5) samples (or with each batch of samples, whichever is

less) add a known amount of the NH3-N standard and reanalyze to confirm recovery.

Recovery of the added NH3-N should be between 95 and 105%. Otherwise, reanalyze the

whole batch.

AMMONIA (ION SELECTIVE ELECTRODE)

PNOC EDC, Philippines

Scope

This test method is applicable to the determination of ammonia (NH3) in acidified water

samples with concentrations from 0.1 to 10 mg/l NH3-N and higher concentrations can be

determined following appropriate dilution.

The sample is made alkaline with sodium hydroxide to convert ammonium to ammonia.

The potential is measured by means of an ion selective electrode (ISE) and the NH3–N

content is read directly from the meter.

Mercury if present forms ammonia complexes, thus causing negative interference.

References

American Public Health Association, American Water Works Association, Water

Environment Federation (1995); American Society for Testing and Material (1994a)


Pipette

Beaker, 150 ml

Volumetric pipette, 100 ml

Combined NH3 electrode with diffusion type membrane

Magnetic stirrer with stirring bar

ISE meter with direct reading concentration scale


1,000 mg/l Ammonia standard as N, NH3-N

Dry NH4Cl, AR, for 1 hr at 100ºC. Dissolve 3.82 g in water and dilute to one liter with

DD water. Alternatively, use commercially available 1000 mg/l NH3-N standard

solutions.

100 mg/l NH3-N: Dilute 100 ml of 1000 mg/l N stock solution to one litre with DD water.

Working standards (0.1 to 10 mg/l NH3 as N): Dilute 100, 10, and 1 ml of the 100 mg/l

standard solution to one litre with DD water.

40% Sodium hydroxide, NaOH: Dissolve 400 g of NaOH, AR, in DD water and dilute to

one litre.

Procedure

Refer to the manufacturer’s instruction manual for proper operation of the meter.

Calibrate the instrument using the working standards. The meter must be recalibrated if

the sample concentration is outside the calibration range.

Transfer 100 ml of the sample (or an aliquot diluted to 100 ml) to a beaker. The sample

temperature must be the same as that of the standards used in the calibration.

Stir the sample gently to prevent air bubbles from being drawn into the solution.

Immerse the electrode into the sample, making sure that no air is trapped on the

membrane of the electrode.

Add 1 ml of NaOH solution to the sample.

When the electrode reaches equilibrium, record the concentration reading as mg/l NH3-N.

Calculation

Calculate mg/l NH3 using:

mg/l NH3 = concentration x 1.214 x dilution factor


Analyze control sample /standard prior to analysis of samples.




preparation. The value determined should be within 10% of the known or expected



the working range.

Check if the slope of the calibration is within the recommended value (-54 to -60 mV)

before carrying out sample measurement.


samples, whichever is less). Acceptance limit for duplicate samples is 10%.


less) add a known amount of the NH3-N standard and reanalyze to confirm recovery.

Recovery of the added NH3-N should be between 90 and 110%. Otherwise, reanalyze the

whole batch.

AMMONIA (NH3-N) (SPECTROHOTOMETRIC WITH NESSLER REAGENT)

Moi University, Kenya

Scope

Ammonia nitrogen is determined through the formation of a colored ammonium

compound, which absorbs light at 425 nm. The method is suitable for ammonia

concentrations in the range 20 g/l to 50 mg/l.

Interferences include turbidity, color, and precipitates of Mg and Ca hydroxides, which

may be removed by distillation or by precipitation with zinc sulphate.

References


Environment Federation (1992), Hatch Co. (1995).

Materials and equipment

Spectrophotometer for use at 400 to 500 nm, with light path of 1 cm or longer

25 ml graduated mixing cylinder

pH meter with high sensitivity electrode

Reagents and standards

Ammonia-free water should be used for all preparations, rinsing, and dilutions. Eliminate

traces of ammonia in distilled water by adding 0.1 ml conc. H2 SO4 to 1 l distilled water

and redistilling.

Stock ammonium solution: Dissolve 3.819 g anhydrous NH4Cl, dried at 100C, in water,

and dilute to 1 l. 1.00 ml of this solution contains 1.00 mg N, or 1.22 mg NH3.

Standard ammonium solution: Dilute 10.00 ml stock ammonium solution to 1000 ml with

water. 1.00 ml of this solution contains 10.00 g N, or 12.2 g NH3.

Sodium hydroxide, 6 N

Dechlorinating agent: Use 1ml of sodium sulphate solution (dissolve 0.9 g Na2SO3 in

water and dilute to 1 l. Prepare fresh daily) to remove 1mg/l residual chlorine in 500 ml

sample.

Neutralizing agents: Prepare with ammonia free water: Sodium hydroxide, NaOH, 1 N;

Sulphuric acid, H2 SO4, 1 N

Sulphuric acid, 0.04 N: Dilute 1.0 ml conc. H2 SO4 to 1 l.

Zinc sulphate solution: Dissolve 100 g Zn SO4.7H2O and dilute to 1 l with water.

Stabilizer reagent: EDTA Reagent: Dissolve 50 g disodium ethylenediamine tetra acetate

dehydrate in 60 ml water containing 10 g NaOH. Heat to dissolve, if necessary. Cool to

room temperature, and dilute to 100 ml.

Nessler Reagent: Dissolve 100 g HgI2 and 70 g KI in a small quantity of water. Add this

mixture, slowly, and with stirring, to a cool solution of 160 g NaOH dissolved in 500 ml

of water. Dilute to 1 liter. Store in rubber-stoppered borosilicate glassware and out of

sunlight. The reagent is stable for up to a year under normal laboratory conditions. Check

reagent to make sure that it yields the characteristic color with 0.1 mg NH3/l within 10

minutes of addition. It should not produce a precipitate with small amounts of ammonia

within 2 hours. CAUTION: Toxic. Do not ingest.

Polyvinyl alcohol

Procedure

Set the spectrophotometer wavelength to 425 nm.

If necessary, remove residual chlorine from freshly collected sample by adding an

equivalent amount of dechlorinating agent.

Add 1 ml ZnSO4 solution to 100 ml sample and mix thoroughly.

Add 0.4 to 0.5 ml NaOH solution to obtain a pH of 10.5, as determined with a pH meter

and electrode, and mix gently.

Let treated sample stand for five minutes. A heavy flocculent precipitate should form,

leaving a clear and colorless supernate.

Clarify by centrifuging or filtering with ammonia-free filter paper.

Fill another 25 ml mixing graduated cylinder to the mark with deionized water (blank).

Add three drops of "mineral stabiliser" to each cylinder.

Invert several times to mix.

Add three drops of polyvinyl alcohol to each cylinder, making sure that the dropping

bottle is exactly vertical.

Invert several times to mix.

Pipette 1.0 ml of Nessler Reagent into each cylinder.

Stopper and invert several times to ensure mixing.

Allow the reaction take place for 1 minute.

Pour each solution into blank and sample cells

Place the blank in the cell holder.

Close the light shield.

Press "ZERO". The display will show 0.00 mg/l after a short waiting period.

Place the prepared sample in the cell holder, and close the light shield.

Press: READ/ENTER.

The concentration of ammonia nitrogen will be displayed in mg/l.

Calculation

Deduct the amount of NH3-N in water used for diluting original sample before computing

final nitrogen value.

Deduct also reagent blank for volume of borate buffer and 6N NaOH solutions used with

sample.

Calculate total NH3-N using:

mgNH3-N/l(51ml final volume)sampleml

A

Where: A = g NH3-N (51 ml final volume)

In case of dilution of sample, multiply result by dilution factor. E.g. if sample was diluted

by a factor of 10, multiply by 10.


For best results, samples should be analyzed immediately after collection from the field.

Geothermal samples usually do not contain residual chlorine; otherwise this should be

destroyed to prevent its reaction with ammonia. If chlorine is suspected to be present, add

0.8 ml conc. H2SO4 to attain a pH of between 1.5 and 2.0, then store at 4C. If such

treatment is used, it is necessary to neutralize the samples with NaOH or KOH

immediately before starting the analysis.

The relative error should be between 0% and 10%.

BICARBONATE, CARBONATE AND TOTAL CARBON DIOXIDE

(TITRIMETRIC)


Scope

This method is applicable to geothermal and groundwater samples with low sulfide and

sulfite contents. It consists essentially of an alkalinity titration corrected for the effects of

other weak acids, mainly boric and silicic acids and ammonium ion, by back titration.

The range of the method is 5 to 500 mg/l HCO3 and can be extended upward using

increased concentrations of HCl/NaOH.

Fresh and air-free samples should be analyzed to avoid interference due to carbon dioxide

absorption from the atmosphere.

Silver nitrate (AgNO3) is added prior to titration to remove H2S interference.

References

Ellis and Mahon (1977); Giggenbach and Goguel (1989).


pH/mV meter

pH electrode

Automatic or digital burettes

Magnetic stirrer with stirring bars

Beakers, 150 ml

Compressed air or nitrogen gas

Volumetric pipette, 50 ml


0.10 N AgNO3: Dissolve 16.987 g AgNO3, AR, crystals in one liter DD water.

1 N NaOH stock solution: Dissolve 40.08 g NaOH in one liter DD water or dilute one

ampoule commercially available 1 N NaOH standard solution to 1 l in a volumetric flask.

0.02 N NaOH titrant: Dilute 20 ml 1 N NaOH stock solution to one liter with DD water.

Standardize with KC8H5O4 (Appendix I.A).

1.0 N HCl stock solution: Dilute 82.6 ml concentrated HCl to one liter or dilute one

ampoule commercially available 1 N HCl standard solution to one liter with DD water in

a volumetric flask.

0.02 N HCl titrant: Pipette 20 ml 1.0 N HCl stock solution into 1 l volumetric flask and

dilute to one liter with DD water. Standardize with NaOH (Appendix I.B)

Procedure

Bicarbonate and total carbon dioxide (Samples with pH less than 8.25)

Calibrate the pH/mV meter according to the instrument’s operating manual using pH 4.00

and pH 7.00 buffer solutions.

Pipette 50 ml sample into a 150 ml beaker and measure pH.

Add 0.10 N AgNO3 dropwise until a white precipitate forms. Adjust pH to original value

by adding either NaOH or HCl.

Titrate to pH 8.25 using 0.02 N NaOH solution. Note the volume dispensed as A. Stir

continuously throughout the titration.

From pH 8.25, titrate to pH 4.5 using 0.02 N HCl solution. Note the volume dispensed as

B. Add HCl to further lower the pH to about pH 2 to 3.

Bubble the sample for 15 minutes with air or nitrogen (high purity). When using air to

remove the dissolved gases in the sample, atmospheric CO2 must be scrubbed off by

passing the air supply through a 6 N NaOH solution.

After bubbling, adjust pH to 4.5 then titrate back to original pH using 0.02 N NaOH.

Note the volume of NaOH used as C.

Continue the titration to pH 8.25 and note the volume of NaOH used to titrate from the

original pH to pH 8.25 as D

Summary of steps

Original pH A B

C

NaOH HCl

D

NaOH NaOH

pH 8.25 pH 4.5

Original pH pH 4.5 pH 8.25

Bubble with high purity Nitrogen Gas or Air with NaOH Scrubber

Bicarbonate and total carbon dioxide (Samples with pH greater than 8.25)

Calibrate the pH/mV meter according to the instrument’s operating manual using pH 4.00

and pH 7.00 buffer solutions.

Pipette 50 ml sample into a 150 ml beaker and measure pH.

Add 0.10 N AgNO3 dropwise until a white precipitate forms. Adjust pH to original value

by adding either NaOH or HCl.

Titrate to pH 8.25 using 0.02 N HCl solution. Note the volume dispensed as A’. Stir

continuously throughout titration.

Continue the titration to pH 4.5 using 0.02 N HCl solution. Note the total volume

dispensed from pH 8.25 to 4.5 as B’. Add HCl to further lower the pH to about pH 2 to

3.


remove the dissolved gases in the sample, atmospheric CO2 must be scrubbed off by

passing the air supply through a 6 N caustic soda solution.

After bubbling, adjust pH to 4.5 then titrate back to pH 8.25 using 0.02N NaOH. Note the

volume of NaOH used as C’.

Continue the titration to the original pH and note the volume of NaOH used from pH 8.25

to original pH as D’.

Summary of Steps

Original pH pH 8.25 pH 4.5

pH 8.25 pH 4.5 Original pH

Bubble with high purity Nitrogen Gas

or Air with NaOH Scrubber

D’

A’

C’

B’

HCl HCl

NaOH NaOH

Calculations

For samples with pH<8.25

mg/l HCO3- = [{(B x NHCl) – (A x NNaOH)} – (C x NNaOH)] x 61017/S

mg/l TCO2 = [(B x NHCl) – {(C + D) x NNaOH}] x 44010/S

For samples with pH>8.25

mg/l HCO3- = [((B’ – A’) x NHCl ) – ((C’ – D’) x NNaOH )] x 61017/S

mg/l CO3= = [(A’ x NHCl ) – (D’ x NNaOH )] x 60000/S

mg/l TCO2 = {(B x NHCl) – (C x NNaOH)} x 44010/S

Where:

NHCl = normality of HCl titrant

NNaOH = normality of NaOH titrant

S = sample aliquot, ml


Ensure that working solutions are standardized.

Prior to analysis, ensure that the slope obtained is within the recommended range.

The standard mV value for pH 7.0 buffer solution at 25ºC should be 0 ± 30 mV. For pH

4.0 buffer solution, the mV value should be approximately 160 mV greater than the pH

7.0 millivolt reading.

Run a NaHCO3 control standard prior to sample measurement and after every ten (10)

samples or every batch of samples, whichever is less. Acceptance limit for control

standard runs is within 5%.

Perform buffer check after every five (5) samples. Determined value should be 0.1 pH

unit of theoretical value. Otherwise, recalibrate the pH meter.

Analyze one set of duplicate samples for every ten (10) samples or with each batch of

samples, whichever is less. Acceptance limit for duplicate samples is 15%.

BORON (TITRIMETRIC WITH MANNITOL)


Scope

This method covers the determination of dissolved boron in acidified water samples.

This titration method is based on the pH change following the addition of mannitol,

which combines with boric acid to release hydrogen ion.

This method is applicable within the concentration range 1 to 100 mg/l boron.

Interferences from dissolved H2S and CO2 can be eliminated by bubbling the acidified

sample.

Reference

Giggenbach and Goguel (1989).


Pipettes, 5, 10 and 20 ml

Beakers, 150 ml


pH meter or autotitrator.

pH glass electrode

Spatula


1 N NaOH stock solution: Weigh 40.08 g NaOH and dissolve in one litre DD water.

Alternatively, dilute one ampoule commercially available 1 N NaOH standard solution to

one litre in a volumetric flask.

0.02 N NaOH titrant: Dilute 20 ml 1.0 N NaOH stock solution to one liter with DD water.

Standardize with KC8H5O4 (Appendix I.A).

Mannitol Powder, AR.

Procedure

Pipette appropriate aliquot of acidified sample into a beaker.


remove the dissolved gases in the sample, scrub off atmospheric CO2 by passing air

through a 6 N caustic soda solution.

Measure pH and add NaOH to adjust pH to 7.30.

Add approximately 5 grams of mannitol powder with continuous stirring.

Titrate sample using standardized 0.02 N NaOH until pH 7.30. Record the volume of the

titrant used.

Calculation

Calculate boron expressed in mg/l using the formula:

mg/l B = V x N x 10810 S

Where:

N = normality of NaOH titrant

V = volume of NaOH used, ml

S = sample aliquot, ml



Analyze the control sample/standard prior to analysis of samples and after every ten (10)

samples, or with each batch of samples, whichever is less. The value determined should

be within 5% of the known or expected concentration. Otherwise, all samples in the

batch should be reanalyzed.

Calibrate the pH electrode using at least two (2) buffers, whose pH should bracket the

expected pH of the sample. Slope should be within 0.95 to 1.05.

Analyze one set of duplicate samples for every ten samples (or with each batch of


Perform buffer check after every ten (10) samples. Determined value should be 0.1 pH

unit of theoretical value. Otherwise, recalibrate the pH meter.

To one sample out of every ten (10) samples (or with each batch of samples, whichever is

less) add a known amount of the analyte of interest and reanalyze to confirm recovery.

Recovery of the added analyte should be between 95 and 105%. Otherwise, reanalyze the

whole batch.

BORON (ICP-ATOMIC EMISSION SPECTROMETRY)

ECGI, China

Scope

This test method covers the determination of boron (B) in filtered acidified samples by

ICP-atomic emission spectrometry (ICP-AES).

The applicable range of this method is from 0.05 to 100 mg/l when using the 249.77 nm

wavelength. This range may be extended upward by dilution of an appropriate aliquot of

sample.

References


Environment Federation (1998). Atom Scan 16 Manual


Inductively Coupled Plasma-Atomic Emission Spectrometer.

Volumetric flasks, 50, 100 , 250 and 1000 ml.

Volumetric pipettes, 1, 5 and 10 ml.

Reagent bottles, 50, 100, 250 and 1000 ml, polyethylene or boron-free

containers

Filter paper, with particle retention of 20-25 µm; Cellulose nitrate membranes (0.45 µm

pore size) are used to filter the sample using a vacuum filtration set-up.


Nitric acid, HNO3, conc. and 1+1.

Argon: Use technical or welder grade. If gas appears to be a source of problems, use

prepurified grade.

1000 mg/l B stock solution

Stock boron solution: Dissolve 571.6 mg anhydrous boric acid, H3BO3, in distilled water

and dilute to 1000 ml ; 1.00 ml=100 g B. Because H3BO3 loses weight with drying at

1050C, use a reagent meeting ACS specifications and keep the bottle tightly stoppered to

prevent entrance of atmospheric moisture.

Standard boron solution: Dilute 10.00 ml stock boron solution to 1000 ml with distilled

water; 1.00 ml = 1.00 g B.

Calibration standard solution (0.05 to 100 mg/l B).

Prepare at least four standards (0.05, 1, 10, 100 mg/l B) to include the expected

concentration of the samples.

Standard blank solution: Acidified DD water (3% HNO3 (v/v)).

Procedure

Optimize the instrument according to instrument’s operating manual. Create a method for

determination of boron. The recommended operating conditions of the Atom Scan16 are

shown in the following table.

ICP-AES operating conditions

Conditions Parameters

Wavelength 249.77 nm

Model Atom Scan16

Generator power 1.15 kw

Plasma gas flow rate 14 l·min-1

Auxiliary gas flow rate 1.0 l·min-1

Nebulizer pressure 0.21 Mpa

Viewing height 15 mm (above the coil)

Sample flow rate 1.0 l·min-1

Integration time dwell time 2 s

Set up instrument as directed. Warm up for 30 minutes.

Calibrate instrument according to manufacturer’s recommended procedure using

calibration standards and blank. Aspirate each standard or blank for a minimum of 15

seconds after reaching the plasma before beginning signal integration. Rinse with

calibration blank or similar solution for at least 60 seconds between each standard to

eliminate any carryover from the previous standard. Use average intensity of multiple

integrations of standards or samples to reduce random error.

Analysis of samples: Begin each sample run with an analysis of the calibration blank,

then check the sample preparation reagents and procedures for contamination. Analyze

samples, alternating them with analysis of calibration blank. Rinse for at least 60 seconds

with dilute acid (specify) between samples and blanks. After each analysis of the

calibration blank, verify that no carry-over memory effect has occurred. If carry-over is

observed, repeat rinsing until proper blank values are obtained. Make appropriate

dilutions if the sample contains a high concentration of salt or the boron concentration is

above the linear calibration range.

Calculation

Calculate concentration of boron (mg/l) in a sample by referring to the calibration curve.

This step can be run automatically by instrumental software. The results can be printed or

displayed directly.

Subtract the result for an adjacent calibration blank from each sample result to make a

baseline drift correction.

If the sample was diluted or concentrated in preparation, multiply results by a dilution

factor (DF) calculated as follows:

mg/l B = Concentration × DF

Where:

DF = final volume/initial volume


Analyze instrument check standard once per 10 samples to determine if significant

instrument drift has occurred. If agreement is not within ±5% of the expected values (or

within the established control limits, whichever is lower), terminate the analysis of the

samples, correct the error, and recalibrate the instrument.

Correct for spectral interference by using computer software supplied by the instrument

manufacturer.

If non-spectral interference correction is necessary, use the method of standard additions.

It is applicable when the chemical and physical form of the element in the standard

addition is the same as in the sample, or the ICP converts the metal in both sample and

addition to the same form. The interference effect is independent of metal concentration

over the concentration range of standard additions; and the analytical calibration curve is

linear over the concentration range of standard additions.

Reanalyze one sample analyzed just before the termination of the analytical run. Results

should agree to within ±5%, otherwise all samples analyzed after the last acceptable

instrument check standard analysis must be reanalyzed.

If the concentration of boron is greater than 100 mg/l, use serial dilution with calibration

blank. Results from the analyses of a dilution should be within ±5% of the original result.

Alternatively, or if the concentration is either below 1 mg/l or not detectable, use a post-

digestion addition equal to 1 mg/l. Recovery of the addition should be either between

95% and 105% or within established control limits of ±2 standard deviations around the

mean.

Analyze the blank and control standard/sample before the samples. The control standard

is prepared separately from the calibration standards. The value determined for the

control standard/sample should be within ±5% of the known or expected concentration.




whole batch.

BORON (ICP-MASS SPECTROMETRY)

BRIUG, China

Scope

This test method covers the determination of boron in filtered acidified samples by high

resolution inductively coupled plasma mass spectrometry (HR-ICP-MS).

The applicable range of this test method is from 0.05 to 100 mg/l when using the HR-

ICP-MS. This range may be extended upward by dilution of an appropriate aliquot of

sample.

For the determination of boron in a filtered aqueous sample aliquot where the total

dissolved salt content of the sample is <1000mg/l, the sample is made ready for analysis

by the appropriate addition of nitric acid, and then diluted to a predetermined volume and

mixed before analysis.

The method comprises the determination of a trace element by ICP-MS, (EPA METHOD

200.8, Revision 5.4). Sample material in solution is introduced by pneumatic nebulization

into radio frequency plasma where energy transfer processes cause desolvation,

atomization and ionization. The ions are extracted from the plasma through a

differentially pumped vacuum interface and separated on the basis of their mass-to-

charge ratio by a double focusing magnetic sector mass spectrometer having a maximum

resolution capability of 7500. The ions transmitted through the mass analyzer are

detected by an electron multiplier and the ion information processed by a data handling

system. Interferences relating to the technique must be recognized and corrected for.

Such corrections must include compensation for isobaric elemental interferences and

interferences from polyatomic ions derived from the plasma gas, reagents or sample

matrix. Instrumental drift as well as suppression or enhancement of instrument response

caused by the sample matrix must be corrected for by the use of internal standards. The

determination of boron is not specifically described in EPA METHOD 200.8, but the

general requirements described including definitions, safety, pollution prevention, waste

management and references are suitable for this procedure.

References

Keith (1996, EPA METHOD 200.8, Revision 5.4).


High resolution inductively coupled plasma mass spectrometer, R 900, concentric

nebulizer for boron, peristaltic sampling pump.

Multi-parameter electric conductivity meter, for total salt content ranging from 0.1 to

1999 mg/l.

Volumetric flasks, 50 ml, 100 ml, 1000 ml (HDPE)

Pipettes

Reagent bottles, 50 ml, 100 ml, 1000 ml (HDPE)


Deionized water with a specific resistance of 17.8 megaohm – cm or greater

Concentrated nitric acid, HNO3, high-grade reagent.

Nitric acid, 2%: 20 ml concentrated nitric acid diluted to 1000 ml with deionized water.

Boron stock standard solution, 1000 mg/l

Commercial boron standard solution for ICP-MS.

Scandium stock standard solution, 10 mg/l

Commercial scandium standard solution for ICP-MS.

Working standard solution (0.05 to 100 mg/l B)

Prepare at least four standards (0.05, 1, 10, 100 mg/l B) to bracket the expected B

concentrations of the samples. All standards are prepared in 2% HNO3 containing 0.050

mg/l Sc.

Standard blank solution / internal standard solution

0.050 mg/l Sc interior standard solution is prepared using scandium stock standard

solution (4.5) and 2% HNO3 (4.3). The internal standard solution is the same as the

standard blank solution.

Quality control samples

Quality control (QC) samples are preferably portions of one or more geothermal water

samples or artificial geothermal water standard samples (boron content ranging from 0.05

to 100 mg/l) that are stable and representative of the samples of interest. These QC

samples can be used to check the validity of the testing process as described in section 7.

All quality control samples are prepared in 2% HNO3 containing 0.050 mg/l Sc prior to

analysis.

Procedure

Check the total salt content of the samples using a multi-parameter electric conductivity

meter (3.2). If the total salt of a sample is higher than 1000 mg/l, dilute the sample to

make sure the total salt content of the sample is below 1000 mg/l. All samples after such

check are prepared in 2% HNO3 containing 0.050 mg/l Sc prior to analysis.

Optimize the instrument according to the instrument’s operation manual. The isotope of 11

B is selected for measurement.

Run the standard blank solution and working standard solutions to establish the

calibration curve for boron using the interior standard calibration method, which is

offered by most ICP-MS systems. The first order linearity of the standard calibration

curve should be such that r20.999.

Run QC samples to check the performance. If the results are within the control limits, go

on the next batch of samples. Any out-of control data should trigger investigation for root

cause(s).

Run filtered acidified samples and read their concentrations. Wash the sample

introduction system for at least 2 minutes using 2% HNO3 between sample introductions.

Note 1: In the procedure, a level of 0.050mg/l Sc as internal standard is added to all

samples, standards and QC samples to give 5×105 or more cps signal.

Note 2: In the procedure, safety, pollution prevention and waste management should be

handled as described in EPA METHOD 200.8 (200.8-8, 200.8-29).

Calculation

Calculate the concentration of boron (mg/l B) in a sample by referring to the calibration

curve. This step can be carried out automatically by most ICP-MS systems. The results

can be printed or displayed directly.

For diluted samples, calculate original concentration of boron in the samples (mg/l B)

using:

Original concentration (mg/l B) = concentration dilution factor

Quality Assurance / Quality Control

Confirm the performance of the instrument or the best procedure by

Analyzing a QC sample

Prior to monitoring the measurement process, the user of the test method needs to

determine the average value and control limits of the QC samples.

It is recommended that, if possible, the type of QC sample that is regularly tested be

representative of the material routinely analyzed. An ample supply of QC sample

material should be available for the intended period of use, and must be stable under the

anticipated storage conditions.

Boron concentration in all reagents should be at minimum. Any cross contamination

among samples or standards should be avoided. Chemical preparation should take place

in clean room.

In order to avoid the interference of 21,22

Ne++

from argon gas in samples, the resolution of

ICP-MS should be greater than 900.


samples, whichever is less). Every ten samples should include one QC sample (4.8) in the

sample sequence analysis. Acceptance limits for duplicate samples or QC samples is

20% for low levels and 10% for high levels. Any out-of control data should trigger

investigation for root cause(s).

To one sample out of every five samples (or with each batch of samples, whichever is

less) add a known amount of the standard and reanalyze to confirm recovery. Recovery

of standard should be between 95 and 105%. Otherwise, reanalyze the whole batch.

BORON (SPECTROPHOTOMETRIC WITH CARMINE)

PNOC EDC CCLS, Philippines

Scope

This method is applicable to acidified water samples containing 1.0-10 mg/l boron.

The test method is based on the color development of carmine or carminic acid in

concentrated sulfuric acid, in the presence of boron, from bright red to bluish red or blue,

which can be analyzed spectrophotometrically at 585 nm.

Silica, fluoride, nitrate and phosphate interfere to some extent.

Reference


Environment Federation (1995).


UV-visible spectrophotometer

Test tubes, 50 ml

Volumetric flasks, 50 ml, polyethylene

Pipettes, 5 and 10 ml

Filter paper, ashless hardened rapid (e.g. Whatman 541)


Hydrochloric acid, AR, HCl, conc.

Sulfuric acid, AR, H2SO4, conc.

Carmine solution: Dissolve 920 mg carmine NF 40, or carminic acid, in 1.0 l con. H2SO4.

Prepare under a hood. Store solution in a polyethylene container.

Working standard solutions (1.0 to 10.0 mg/l B): Prepare at least four standards to

bracket the expected concentration of the samples.

Procedure

Pipette 2 ml standards and samples into 50 ml test tubes.

Add 2 drops conc. HCl.

Carefully introduce 10 ml conc. H2SO4. Mix and allow to cool to room temperature.

Carefully add 5 ml carmine solution. Mix well. Leave solution for 45-60 minutes.

Prepare a reagent blank by treating a 2 ml aliquot of DD water.

Switch on UV-Vis spectrophotometer and allow to warm up for at least 30 mins.

Measure the absorbance of the standards and samples at 585 nm against the reagent

blank.

Calculation

Read boron concentration in mg/l directly from the instrument or prepare standard

calibration curve to read the sample concentration.

For diluted samples, calculate the original concentration using:

mg/l B = concentration x dilution factor


Always include reagent and sample blanks in the analysis.


the working range. Dilute samples if necessary.

Absorbance values should be within the acceptable working range, as specified in the

manufacturer’s manual.

Check that the first order linearity of the standard calibration curve has r2 0.995.

Ensure that the absorbance to concentration ratio of the calibration standards is consistent

within 95% confidence range of previously established values. Discard standards, which

deviate from acceptable ratio.

Analyze the reagent blank and control standard/sample before analyzing samples. The

control standard is a separate preparation from the calibration standards. The value

determined for the control sample should be within 10% of the known or expected

concentration.

Analyze samples in duplicate. Acceptance limit is 10%.

Analyze the reagent blank, check standard and control sample/standard after every five


from one of the calibration standards. The determined values should be within 10% of

the known or expected concentration. Otherwise, all samples in the batch should be

reanalyzed.



of standard should be between 90 to 110%. Otherwise, reanalyze the whole batch.

Check that the result has been multiplied by the dilution factor if dilution was needed.

BORON (SPECTROPHOTOMETRIC WITH CURCUMIN)

ICE, Costa Rica

Scope

This method covers the determination of boron (B) in filtered and unfiltered samples by

means of UV-Vis spectrophotometry.

The method is based on the formation of a complex between boron and curcumine in

concentrated sulfuric – acetic acids, which can be analyzed spectrophotometrically at 540

nm. The applicable range of this method is from 0.1 to 2.0 mg/l. This range may be

extended upward by dilution of an appropriate aliquot of sample.

Nitrite interferes in concentrations above 3 mg NO2/l.

References

American Public Health Association, American Water Works Association and Water

Environment Federation (1998); Barbolani Piccardi (1973).


Spectrophotometer UV-Vis.

Polyethylene beakers, 50 ml.

Pipettes, 1-25 ml.

Volumetric flasks, 100 ml, 1 l.

Micropipette 100 – 1000 l


Concentrated sulfuric acid, H2SO4.

Glacial acetic acid, HAc.

Curcumin solution: Weigh 0.125 g of curcumin reagent, dissolve and dilute to 100 ml

with glacial acetic acid. Since this curcumin solution is unstable, it is recommended to

prepare only the amount necessary for the analysis.

“Acid” reagent: Mix equal volumes of concentrated H2SO4 and glacial HAc.

Ammonium acetate-glacial acetic acid reagent: Dissolve 25 g of ammonium acetate in

DD water, add 30 ml of glacial HAc and dilute to 100 ml with DD water.

1000 or 100 mg/l, B stock solution: For the 1000 mg/l B stock solution, dilute one

ampoule of commercially available 1000 mg/l B standard to one liter with the appropriate

solvent (DD water or 0.1 mole/l HCl, follow the manufacturer’s instructions).

Alternatively, dissolve 0.5720 g of anhydrous boric acid, H3BO3, in DD water and dilute

to 1000 ml to give a 100 mg/l stock solution.

Working standard solutions (0.1 – 2.0 mg/l B): Prepare at least four standards to bracket

the expected concentration of the samples.

Amidosulfuric acid (H2NSO3H) 6% solution: Dissolve 6.0 g of amidosulfuric acid

reagent – grade in 100 ml of DD water.

Procedure

Optimize the instrument according to instrument’s operating manual.

Make a suitable dilution of samples with high B content, so that the concentration falls

within the working range.

For nitrite concentration of the sample > 3 mg/l:

Pipette a 20.0 ml aliquot of sample into a 25 ml volumetric flask.

Add 4.0 ml of a 6 % amidosulfuric acid solution.

Wait for 4-6 minutes and then dilute to the mark with DD water.

Pipette a 0.5 ml aliquot each of the blank, standards and samples into 50 ml plastic

beakers.

Add 3.0 ml of the curcumin solution. Mix well.

Add 3.0 ml of the acid reagent. Mix well.

Leave the solutions for 1 hr.

After 1 hour. , add 15.0 ml of the ammonium acetate – glacial acetic acid solution.

Read the spectrophotometer at 540 nm.

Calculation

Calculate the concentration of B (mg/l) by referring to the calibration curve.

For diluted samples, calculate the original concentration of B using:

mg/l B = concentration x dilution factor.

Quality Assurance/Quality control



the working range. Dilute samples accordingly.

Absorbance values should be within the acceptable working range.

Check that the first order linearity of the calibration curve has r2 0.999

Analyze the blank and control standard/sample before analyzing samples.

Analyze the reagent blank; check standard after every ten samples, or with each batch of

samples, whichever is less. The check standard is chosen from one of the calibration

standards, while the control standard/sample is a separate preparation. The determined

value should be within 5% of the known or expected concentration. Otherwise, all

samples in the batch should be reanalyzed.



of standard should be between 90 to 110%. Otherwise, reanalyze the whole batch.

BORON (SPECTROPHOTOMETRIC WITH AZOMETHINE-H)

PNOC EDC Philippines

Scope

This method is applicable to untreated water samples containing 0.10-10-mg/l boron.

The test method is based on the complexation of boron with azomethine-H to form a

yellow complex, which can be analyzed Spectrophotometrically at 410 nm.

EDTA in buffer solution is used as masking agent to eliminate interferences from

complexing metals.

References

Cogbill and Yoe (1955); Krug et al. (1981);

Edwards (1980); Kirst and Rump (1992); Shucker et al. (1975).


UV-visible spectrophotometer

Volumetric flasks, 50 ml, PE

Volumetric pipettes, 5 and 10 ml

Filter paper, ashless hardened rapid (e.g. Whatman 541)

Filter paper, 0.45, (Whatman 5 or equiv.)

Erlenmeyer flask, 50 ml, polyethylene


Glacial acetic acid, AR, C2H4O2

Ammonium acetate, AR, C2H7NO2

EDTA disodium salt, AR, C10H18N2Na2O10

Ascorbic acid, AR, C6H8O6

Buffer solution, pH 5.9: Dissolve 3.0 g EDTA disodium salt in 75 ml DD water. Add 125

ml glacial acetic acid and 250 g ammonium acetate. Stir and gently heat to dissolve all

solids. Prepare solution under a fume hood.

Azomethin H powder, AR, C17H12NNaO8S2

Azomethine-H reagent: Dissolve 0.98 g Azomethin H powder in 80 ml cold DD water.

Add 1.0 g ascorbic acid and stir. Filter the solution and adjust its volume to 200 ml.

Store in amber PE container and keep cool in a refrigerator. Prepare fresh solution daily.

Working standard solutions (0.10 to 3.00 mg/l B): Prepare at least four standards to


Procedure

Filter samples.

Pipette 15 ml standards and samples into 50 ml polyethylene Erlenmeyer flasks.

Add 5 ml buffer solution and 5 ml azomethine-H reagent. Mix well and allow to stand for

1 hour.

Prepare a reagent blank by treating 15 ml aliquot of DD water.

When necessary to correct for turbidity, treat 15 ml of sample with buffer solution only.

Switch on UV-VIS spectrophotometer and allow to warm up for at least 30 mins

Measure the absorbance of the standards and samples at 410 nm against the reagent

blank.

Calculation

Read boron concentration in mg/l directly from the instrument or prepare standard

calibration curve to read the sample concentration.


mg/l B = concentration x dilution factor

For turbidity correction, subtract corresponding turbidity blank concentration from

sample concentration.










deviate from the acceptable ratio.

Analyze the reagent blank and control standard/sample before analyzing samples. The

control standard is a separate preparation from the calibration standards. The determined

value of the control sample should be within 5% of the known or expected

concentration.




from one of the calibration standards. The determined values should be within 5% of the

known or expected concentration. Otherwise, all samples in the batch should be

reanalyzed.





BORON (ATOMIC ABSORPTION SPECTROPHOTOMETRY)

GESAL, El Salvador

Scope

This test method covers the determination of boron (B) usually present in geothermal

waters, in filtered acidified samples (pH 1.2-1.5) by atomic absorption spectrophotometry

(AAS). The applicable range for this method is from 30 to 300 mg/l when using the 249.8

nm wavelength.

In flame atomic absorption spectrophotometry, a sample is aspirated into a flame and

atomized. A light beam is directed through the flame in a monochromator, and into a

detector where the amount of light absorbed by the atomized element in the flame is

measured. For some metals, atomic absorption exhibits superior sensitivity over flame

emission. Since each metal has its own characteristic absorption wavelength, a source

lamp composed of that element is used; this makes the method relatively free from

spectral or radiation interferences. The amount of energy at the characteristic wavelength

absorbed in the flame is proportional to the concentration of the element in the sample

over a limited concentration range.

Sodium has been found to cause interference when the ratio of sodium to boron is very

high. The effect is usually minimized by adjusting the flame to neutral stoichiometry (red

cone 0.5-1 cm high) with consequent loss of sensitivity.

References


Environment Federation (1995); Skoog and Leary (1994).


Atomic absorption spectrophotometer.

Boron hollow cathode lamp

Volumetric flasks, 50, 100 and 200 ml.

Volumetric pipettes 2, 5 and 10 ml.

500 ml plastic flasks.

Filter paper, Whatman No. 42

Pumping system to introduce and automatically dilute sample (SIPS)


Concentrated nitric acid, HNO3

Acetylene gas with purity of at least 98.0 % vol.: Acetone is always present in acetylene

cylinders and can be prevented from entering and damaging the burner system by

replacing a cylinder when only 80-psig acetylene remain.

Air compressor, cleaned and dried through a suitable filter to remove oil, water, and other

foreign substances.

Nitrous oxide gas with purity of at least 99.2 %.

Fit nitrous oxide cylinder with a special nonfreezable regulator or wrap a heating coil

around an ordinary regulator to prevent flashback at the burner caused by a reduction in

nitrous oxide flow through a frozen regulator.

Acidified DD water: Add 10 ml concentrated HNO3, AR, for every 500 ml DD water.

Boron acidified standard solution of 1000 mg/l:

Boron stock solution may be purchased as certified solution or prepared as described

below: Do not dry but keep bottle tightly stoppered and store in a desiccator. Dissolve

0.5716 g anhydrous H3BO3 in water and dilute to 1000 ml; 1ml = 100 µg B.

Working standard solutions (50.0 to 200 mg/l of boron): Prepare at least four standards to


Standard blank solution: Add 2 ml concentrated HNO3 to 100 ml DD water

Procedure

Optimize the instrument according to instrument’s operating manual (follow the safety

guidelines specified by the equipment manufacturer).

Wash the sample auto dilution system to eliminate any type of contaminants in the whole

pumping system. Also wash the burner and nebulizer.

Verify the sensitivity and stability of the signal using the highest concentration standard

prepared for the calibration curve, (e.g. for a wavelength of 249.8 nm one 400 mg/l

standard must read 0.2 of absorbance).

When signal is stable, proceed to set instrument to zero absorbance and then prepare the

calibration curve manually with the help of a sample dilution system. This means that the

equipment will read the blank and then the standards from smaller to greater

concentration and the equipment program will subtract the blank absorbance from each

standard until a calibration curve of linear type is obtained. In the auto dilution system

program there is a washing step after the completion of the calibration curve.

In case the auto dilution system program is not present, proceed to prepare standards of

50, 100, 150, and 200 mg/l and generate the calibration curve.

After the calibration read the values for the standards.

Read values for one control standard/sample and fourteen samples. Rinse the system after

every sample reading.

If the concentration of a sample is out of range of the calibration curve, introduce to the

auto dilution program a suitable dilution factor. If an auto dilution system is not available,

choose the respective dilutions.

Recalibrate the system after fourteen samples.

Calculations

Read mg/l B from the calibration curve.

For diluted samples, calculate original mg/l B using:

mg/l B = boron concentration x dilution factor


All samples must be filtered and acidified in advance to keep the analytes in solution.





manufacturer's manual.


Analyze the control standard/sample before analyzing samples. The control standard is a

separate preparation from the calibration standards. The percentage difference between

the concentration value determined by the equipment and the theoretical one must be

within ± 5%.

Recalibrate the equipment after every fourteen samples. Analyze the control

standard/sample after recalibration verifying the percentage difference between the

theoretical and obtained values. If the results are out of range, a new calibration must be

carried out.




CALCIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY)


Scope

This test method covers the determination of calcium (Ca) in filtered acidified samples by

atomic absorption spectrophotometry (AAS).

The applicable range of this test method is from 0.2 to 20 mg/l when using the 422.7 nm

wavelength. This range may be extended upward either by dilution of an appropriate

aliquot of sample or rotating the burner head.

Lanthanum oxide is added to arrest interferences such as from sulfate, phosphate,

aluminum, silica and nitrate.

References


Environment Federation (1995); American Society for Testing and Material (1995b).


Atomic absorption spectrophotometer

Ca hollow cathode lamp

Volumetric flasks, 50 and 100 ml

Automatic dispenser

Pipettes, 1-10 ml

Erlenmeyer flasks, 50 ml, preferably plastic.

Reagent bottles, 1 l and 250 ml, plastic

Filter paper, with particle retention of 20-25 µm


Concentrated hydrochloric acid, HCl

50% nitric acid, HNO3: Mix equal volumes of DD water and concentrated HNO3.

50 mg/l La as lanthanum oxide, La2O3: Wet 58.7 g La2O3, AR, in DD water. Add 250 ml

of concentrated HCl slowly to the mixture. When dissolved, dilute to 1000 ml with DD

water.

Acetylene gas with purity of at least 99.5 vol %: Acetone, which is always present in

acetylene cylinders, can be prevented from entering and damaging the burner system by

replacing a cylinder when only 75-psig acetylene remain.

Compressed air is cleaned and dried by passing it through a suitable filter to remove oil,

water, and other foreign substances.

Acidified DD water: Add 1 ml concentrated HNO3, AR, for every liter DD water.

1000 mg/l Ca stock solution: Dry about 3 g CaCO3 to constant weight at 105ºC. Suspend

2.497 g CaCO3 in DD water and dissolve cautiously with a minimum amount of 50%

HNO3. Add 10 ml concentrated HNO3 and dilute to 1 liter. Alternatively, dilute one

ampoule of commercially available 1000 mg/l Ca standard with acidified DD water.

Working standard solutions (0.20 to 20 mg/l Ca): Prepare at least four standards to


Standard blank solution: Add 1 ml La2O3 suppressant for every 10 ml acidified DD

water.

Procedure


Dilute samples with high Ca so that the concentration falls within the standard calibration

curve. Pipette 10 ml of the sample to a 50 ml Erlenmeyer flask and add 1 ml La2O3. Mix

well.

Aspirate the reagent blank and zero the instrument.

Aspirate each standard in turn into the flame and record the absorbance. Aspirate

acidified DD water between standards.

Aspirate samples and read the absorbance. Atomize acidified DD water between samples.

Calculation

Calculate mg/l Ca by referring to the calibration curve.

For diluted samples, calculate original mg/l Ca using:

mg/l Ca = concentration x dilution factor


Acidified DD water must be used in the preparation of samples/standards.


Add suppressant to blanks, standards and samples.






Analyze the blank and control standard/sample before analyzing samples. The control

standard is a separate preparation from the calibration standards. The value determined

for the control standard/sample should be within 5% of the known or expected

concentration.


samples, whichever is less). Acceptance limits for duplicate samples is 15% for low

levels and 5% for high levels.

Analyze the reagent blank, check standard and control sample/standard after every ten






less) add a known amount of the metal of interest and reanalyze to confirm recovery.

Recovery of the added metal should be between 95 and 105%. Otherwise, reanalyze the

whole batch.


CALCIUM (ICP-ATOMIC EMISSION SPECTROMETRY)

ECGI, China

Scope

This test method covers the determination of calcium (Ca) in filtered acidified samples by

ICP-atomic emission spectrometry (ICP-AES).

The applicable range of this method is from 0.025 to 500 mg/l when using the 317.93 nm

wavelength.

The sample is introduced into the instrument as a stream of liquid that is converted inside

the instrument into an aerosol and then transported to the plasma where it is vaporized,

atomized, and ionized. The excited atoms and ions emit their characteristic radiation,

which is collected and sorted by wavelength. The radiation is detected and turned into

electronic signals that are converted into concentrations.

The sample matrix can cause physical interferences and total salt concentrations of more

than 0.5 % might cause ionization and viscosity interferences.

References

American Public Heath Association, American Water Works Association and Water

Environment Federation (1998); ICP-AES. instrument operating manual.


Inductively Coupled Plasma-Atomic Emission Spectrometer.


Pipettes, 1, 5 and 10 ml.

Reagent bottles, 250 and 1000 ml.

Filter paper, with particle retention of 20-25 µm; Cellulose nitrate membranes (0.45 µm

pore size) are used to filter the sample using vacuum filtration set-up.


Nitric acid, HNO3, conc. and 1+1.

Argon: Use technical or welder grade. If gas appears to be a source of problems, use

prepurified grade.

1000 mg/l Ca stock solution

Dry about 3 g CaCO3 to constant weight at 105°C, suspend 2.497 g CaCO3 in DD water

and dissolve cautiously with a minimum amount of 50% HNO3.

Add 10 ml concentrated HNO3 and dilute to 1 liter.

Working standard solutions (50 to 500 mg/l Ca). Prepare at least four standards to bracket


Standard blank solution

Acidified DD water (5% HNO3 (V/V)).

Procedure

Optimize the instrument according to instrument’s operating manual. Create a procedure

for the determination of calcium. The recommended operating conditions of the Atom

Scan16 are shown in the following table.

ICP-AES operating conditions

Conditions Parameters

Wavelength 317.9 nm

Model Atom Scan 16

Generator power 1.15 kW

Plasma gas flow rate 14 l min-1

Auxiliary gas flow rate 1.0 l min-1

Nebulizer pressure 0.21 Mpa

Viewing height 15 mm (above the coil)

Sample flow rate 1.0 l·min-1

Integration time dwell time 2 s

Set up instrument as directed. Warm up for 30min.

Calibrate instrument according to manufacturer’s recommended procedure using

calibration standards and blank. Aspirate each standard or blank for a minimum of 15 s

after reaching the plasma before starting signal integration. Rinse with calibration blank

or similar solution for at least 60 s between standards to eliminate any carry-over from

the previous standard. Use average intensity of multiple integrations of standards or

samples to reduce random error.

Before analyzing samples, analyze instrument check standard. Concentration values

obtained should not deviate from the actual values by more than ±5%.

Analysis of samples: Begin each sample run with an analysis of the calibration blank,

then analyze the sample preparation reagents and take action in case of contamination.

Analyze samples, alternating them with analyses of calibration blank. Rinse for at least

60 s with dilute acid between samples and blanks. After introducing the calibration blank

each time verify that no carry-over memory effect has occurred. If carry-over is observed,

repeat rinsing until proper blank values are obtained. Make appropriate dilutions if the

sample contains a high concentration of salt or the calcium concentration is beyond the

linear calibration range.

Calculation

Calculate concentration of calcium (mg/l) in a sample by referring to the calibration

curve. This step can be run automatically by instrumental software. The results can be

printed or displayed directly.

Subtract the result for an adjacent calibration blank from each sample result to make a

baseline drift correction.

If the sample was diluted or concentrated in preparation, multiply results by a dilution

factor (DF) calculated as follows:


Analyze instrument check standard once per 10 samples to determine if significant

instrument drift has occurred. If agreement is not within ±5% of the expected values (or

within the established control limits, whichever is lower), terminate analysis of samples,

correct problem, and recalibrate instrument.

Correct for spectral interference by using computer software supplied by instrument

manufacture.

If non-spectral interference correction is necessary, use the method of standard additions.

It is applicable when the chemical and physical form of the element in the standard

addition matrix is the same as in the sample or when the ICP converts the metal in both

sample and addition matrix to the same form. The interference effect is independent of

metal concentration over the concentration range of standard additions; and the analytical

calibration curve is linear over the concentration range of standard additions.

Reanalyze one sample analyzed just before termination of the analytical run. Results

should agree to within ±5%, otherwise all samples analyzed after the last acceptable

instrument check standard analysis must be reanalyzed.




whole batch.

CALCIUM (TITRIMETRIC WITH EDTA)

ICE, Costa Rica

Scope

This method covers the determination of calcium Ca in filtered acidified samples by

means of titration with EDTA. The endpoint of the titration is determined by means of a

Ca+2

ion selective electrode.

The applicable range of this method is from 10 – 100 mg/l. This range may be extended

upward by dilution of an appropriate aliquot of sample.

Magnesiun in concentrations above 2 mg/l interferes if the pH is not adjusted properly.

Reference




Autotitrator (Radiometer Tim 900).

Calcium ion selective electrode

Reference electrode.

Pipettes 1, 2, 10, 25 ml


Beakers, 50 ml


EDTA disodium salt 0.01 mole/l. Weigh 3.75 g of reagent-grade disodium

ethylenediaminetetraacetate dihydrate, C10H14N2Na2O82H2O, MW 372.24, dissolve in

distilled water and dilute to 1000 ml. Standardize against a standard calcium solution as

described in 4.3.

Buffer solution, ammonium chloride - ammonia. Dissolve 6.75 g of ammonium chloride,

NH4Cl, in 57 ml of concentrated ammonium hydroxide, NH4OH (d = 0.90 g/ml), and

dilute to 100 ml with distilled water.

Calcium standard solution, 0.008 mole/l. Weigh 0.4000 g of anhydrous calcium

carbonate (volumetric standard grade). Transfer the solid to a 500 ml volumetric flask

using 100 ml of distilled water, add drop wise 1 + 1 HCl until all CaCO3 has dissolved.

Dilute to the mark with distilled water.

1000 mg/l, Ca stock solution. Weigh 1.000 g of anhydrous CaCO3 (primary standard)

into a 500-ml Erlenmeyer flask. Add slowly 1 + 1 HCl until all CaCO3 has dissolved.

Add 200 ml of distilled water and boil for a few minutes to expel CO2. Cool, add a few

drops of methyl orange indicator, and adjust to the intermediate orange color by adding

3N NH4OH or 1 + 1 HCl, as required. Transfer quantitatively and dilute to 1000 ml with

distilled water. Alternatively, dilute one ampoule of commercially available 1000 mg/l

Ca standard with the appropriate solvent (DD water or 0.1 mole/l HCl, follow the

manufacturer’s instructions).

Procedure

Standard EDTA titration, 0.01 mole/l.

Optimise the instrument according to instrument´s operating manual.

Place a 2.00 ml aliquot (A) calcium standard solution (0.008 mole/l) in a 50 ml beaker.

Add 1.0 ml of the buffer solution. Mix well.

Place the electrodes in the solution and titrate with the EDTA solution.

The end point of the titration is detected automatically by the instrument. Record the

volume (B).

Titration of geothermal samples

Optimise the instrument according to instrument´s operating manual.

Make a suitable dilution of samples with high Ca content, so that the concentration falls

within the working range (10 – 100 mg/l).

Pipette a 10.0 ml aliquot of sample (D) into a 50 ml beaker.

Add 1.0 ml of the buffer solution. Mix well. The pH should be about 12-13. If not it

should be adjusted to such a value.

Add 25 ml of distilled water.

Place the electrodes in the solution and titrate with the EDTA standard solution.

The end point of the titration is detected automatically by the instrument. Record the

volume used (C). The instrument can be programmed to calculate the calcium

concentration.

If an autotitrator is not available, the endpoint can be determined using a pH/mV meter

with a Ca+2

ion selective electrode, as follows:

Fit the meter with the electrodes (or combination electrode) inside the beaker.

Stir the solution and record the mV reading.

Add 0.5-1.0 ml portions of EDTA standard solution from the burette, stir and read the

mV.

Repeat the addition of 0.5 ml portions of titrant, stirring and measuring the mV after

every addition, until near the expected endpoint.

Add 0.1 ml or less of titrant and record the mV reading after each addition. Continue the

additions until the equivalence point has been passed by 1.0-2.0 ml.

Plot the titration curve (mV vs volume of EDTA added). The equivalence point is the

volume corresponding to the steepest part of the curve.

The endpoint can also be determined using an appropriate indicator, such as Murexide,

Eriochrome Blue Black R (CI 222), or Eriochrome Black T (CI 14645).

Calculation

Calculate the concentration of the calcium standard solution using:

[Ca] = g / (MW x Vol) , mole/l

Where:

Ca = calcium concentration, mole/l,

g = grams of CaCO3,

MW = formula weight, CaCO3 (100.09 g/mole)

Vol = final volume

Calculate the concentration of the EDTA solution using:

[EDTA] = M x A/B, mole/l

Where:

EDTA = EDTA concentration, mole/l

M = concentration of the calcium standard solution

A = volume of the calcium standard solution used.

B = ml titrant (EDTA).

Calculate the concentration of Ca (mg/l) in the samples using:

mg/l Ca = CEDTA x C x 40.09 x 1000/ml sample (D)

Where:

CEDTA = concentration of EDTA standard solution

C = ml titrant (EDTA).

D = sample volume, ml.

For diluted samples, calculate the original concentration of Ca using:

mg/l Ca = concentration x dilution factor

Quality Assurance/Quality control.


Sample concentrations should be within the working range. Dilute samples accordingly.

Analyze the blank and control standard/sample before analyzing samples.

Analyze the reagent blank, control standard after every ten samples, or with each batch of

samples, whichever is less. The value determined should be within 1% (5% is

acceptable) of the known or expected concentration. Otherwise, all samples in the batch

should be reanalyzed.




whole batch.

CALCIUM (ION CHROMATOGRAPHY)

DOE, Philippines

Scope

This method is applicable to the determination of calcium (Ca) by chemically suppressed

ion chromatography. The method detection limit for the above analyte determined from

replicate analyses is 0.02 - 50mg/l and can only be extended to 100 mg/l by dilution. The

methods works best at relatively low calcium concentrations.

Sample is filtered using a 0.45 m membrane filter.

An aliquot of the sample is pumped through an ion-exchange column where the cation(s)

of interest is (are) separated. Because different ions have different migration rates, the

sample ions elute from the column as discrete bands. The sample ions are selectively

eluted off the separator column and onto a suppressor column. The eluent ions are

neutralized and the sample ions are converted to their corresponding strong bases and are

detected in a conductance cell. The chromatogram produced is displayed in an integrator

for measurement of peak height or area. The ion chromatograph is calibrated with

standard solutions containing known concentrations of the cation(s) of interest.

Interferences can be caused by substances with retention times that are similar to and

overlap those of the cation or anion of interest. Large amounts of an anion/cation can

interfere with the peak resolution of an adjacent analyte. Sample dilution and/or

fortification can be used to solve most interference problems associated with retention

times.

References

Dionex Application Notes, Keith (1996, EPA Method 300.7).


Ion Chromatograph

Cation Guard Column

Cation Separator Column

Cation Suppressor Column

Conductivity Detector

Gradient Pump

Integrator

Balance, Analytical – capable of accurately weighing to the nearest 0.0001 g

Pipettes, 1.0 to 20.0 ml

Volumetric flasks, 20.0 to 1000.0 ml

Syringe, 1 ml capacity

Nitrogen gas, ultra high purity


20 mM methane sulfonic acid (eluent): Pipette 1.80 ml of 99% Methane sulfonic acid

(MSA) into a 1 l volumetric flask and dilute to volume with reagent water.

Calcium stock solution (1000 mg/l): Dissolve 2.4970 g of calcium carbonate (CaCO3) in

reagent water and dilute to 1 l or prepare using commercially available calcium standard.

Mixed cation standard

Working standard solutions: Prepare at least four or five standards to bracket the

expected concentration of the analyte.

Reagent water. Filtered, deionized (Specific conductance 18 ohms) and degassed

Procedure

Chromatographic Conditions

Column: CS12-4mm (ethylvinylbenzene cross-linked w/55%

divinylbenzene)

Eluent: 20 mM Methane sulfonic acid

Flow rate: ml/min

Injection Vol: 50l

Detection: Suppressed Conductivity

Background Reading: 1-3S

Output Range: 30S

Start-up the equipment according to manual’s instructions.

Set desired integrator parameters

Chart speed:0.5

Attenuation:1024

Peak Threshold: 10000

Equilibrate the system by pumping eluent through the column and detector until a stable

baseline is obtained.

Inject the laboratory reagent blank (LRB).

Inject calibration standards. Calibration standards are stable for one week when stored at

4oC in high-density polyethylene containers.

When calibration is established, record peak height or area, and construct calibration

curve.

Inject the LRB.

Inject the samples. Flush the sampling system thoroughly with each new sample.

Verify calibration curve after every ten samples and at the end of each day’s analyses.

Calculation

Calculate concentration of the analyte from the calibration curve

For diluted samples, calculate calcium content as follows

mg/l Ca = Concentration x dilution factor

Report data in mg/l. Do not report data lower than the lowest calibration standard.

An integration system may also be used to provide a direct readout of the concentration

of the analyte of interest.


The laboratory must add a known amount of analyte to a minimum of 10% of the routine

samples. In each case the laboratory fortified matrix (LFM) aliquot must be a duplicate of

the aliquot used for sample analysis. The analyte concentration must be high enough to

be detected above the original sample and should not be less than four times the method

detection limit.

If the concentration of fortification is less than 25% of the background concentration of

the matrix, the matrix recovery should not be calculated.

Calculate the percent recovery for each analyte, corrected for concentration measured in

the unfortified sample, and compare these values to the designated LFM recovery range

of 90-110%.

Until sufficient data becomes available (usually 20-30 analyses), assess laboratory

performance against recovery limits. When sufficient internal performance data becomes

available develop control limits from percent mean recovery and standard deviation.

If the recovery of any analyte falls outside the designated LFM recovery range and the

laboratory performance for the analyte, the recovery problem encountered with the LFM

is judged to be either matrix or solution related, not system related.

In recognition of the rapid advances taking place in chromatography, the analyst is

permitted certain options, such as the use of different columns and/or eluents to improve

the separation or lower the cost of measurements.




whole batch.

CHLORIDE (ARGENTOMETRIC TITRATION)


Scope

This test method is applicable to the measurement of chloride in low to highly

mineralized water.

This test method is based upon the Mohr procedure for determining chloride ion with

silver nitrate. The chloride ion reacts with silver ion before any silver chromate forms,

due to lower solubility of silver chloride. The potassium chromate indicator reacts with

the excess silver ion to form a red silver chromate precipitate. The end point is the

appearance of the first permanent orange color.

Samples containing 5 to 150,000 mg/l of chloride can be analyzed by this method. These

chloride levels can be determined by varying sample aliquot and using the appropriate

titrant concentration.

Sulfide, bromide, iodide, thiocyanate, cyanide, phosphate, sulfite, carbonate, hydroxide,

and iron interfere in this method. Sulfide, sulfite, and thiosulfate can be removed by

peroxide treatment, but usually no attempt is made to remove bromide and iodide because

they are usually present in insignificant quantities compared to chloride. If necessary, the

pH can be raised and the hydroxides of several metals, including iron, can be filtered off.

Iron, barium, lead, and bismuth precipitate with the chromate indicator.

References

American Public Health Association, American Water Works Association, Water and

Environment Federation (1995); American Society for Testing and Material. (1994b).


Filter paper, 20-25 m particle retention

Beaker, 150 ml

Dropper

Pipettes, 10, 20 and 50 ml

Automatic or digital burette



0.1 N Silver nitrate, AgNO3, for high chloride concentration: Dissolve 16.987 g AgNO3,

AR, in one liter DD water and standardize or dilute 1 ampoule commercially available

0.1 N AgNO3 to 1 liter with DD water and standardize (see p. 126). Store in an amber

bottle.

0.01 N Silver nitrate, AgNO3, for low chloride concentrations: Dissolve 1.699 g AgNO3,

AR, in one liter DD water and standardize. Alternatively, dilute 100 ml 0.1 N AgNO3 to

1 liter with DD water and standardize (see p. 126). Store in an amber bottle.

Nitric acid solution, HNO3: Add 1 volume of concentrated HNO3 to 19 volumes of water.

Chloride standard, 1000 mg/l Cl for 0.1 N AgNO3: Dissolve 1.65 g NaCl (dried at 110 ºC

for one hour) in a small amount of DD water. Add 2 ml HNO3 and dilute to mark with

DD water or alternatively, prepare using commercially available standards.

Chloride standard, 100 mg/l and 10 mg/l for 0.01 N AgNO3: Prepare by serial dilution

from 1000 mg/l Cl standard or alternatively, prepare using commercially available

standards.

Sodium bicarbonate, NaHCO3, AR or Calcium carbonate, CaCO3, AR

Potassium chromate indicator solution: Dissolve 50 g K2CrO4 in a small amount of DD

water. Add AgNO3 solution until a definite red precipitate is formed. Leave for 12 hours,

filter and dilute to 1 liter with DD water.

Procedure

Pipette 20 ml aliquot of 1,000 mg/l Cl standard into a 150 ml beaker to standardize the

0.1 N AgNO3 for high Cl analysis. For low Cl, use 100 ml of 10 mg/l Cl standard to

standardize 0.01 N AgNO3.

Add 1 ml chromate indicator, 1 g of NaHCO3 or CaCO3 powder, and titrate with

continuous stirring until the appearance of first permanent orange color preceding a red

precipitate. Record the volume of AgNO3 used.

Filter the sample to remove any insoluble or suspended materials.

Pipette 5 to 100 ml aliquot of sample into a 150 ml beaker. Choose sample aliquot so that

0.15 to 10 mg Cl- is present in the portion to be titrated.

Add 1 g of NaHCO3 or CaCO3 powder and stir to dissolve. Ensure that the resulting pH is

between 6.5 to 8.5.

Add 1 ml chromate indicator.

Titrate with the appropriate AgNO3 solution to a permanent orange color preceding the

brick red colored precipitate.

Record the volume of AgNO3 required to reach the end point and calculate the chloride

concentration in mg/l.

Calculation

mg/l = 35453VN/S

Where:

V = ml of silver nitrate used

N = normality of silver nitrate

S = sample aliquot in ml



Analyze check standard and control sample/standard prior to analysis of samples and

after every ten (10) samples, or with each batch of samples, whichever is less. The

determined value should be within 5% of the known or expected concentration.

Otherwise, all samples in the batch should be reanalyzed.






whole batch.

CHLORIDE (POTENTIOMETRIC TITRATION)


Scope

This test method covers the determination of chloride in natural waters and geothermal

brine where the concentration is 5 mg/l.

Chloride is determined by a potentiometric titration with silver nitrate solution with a

glass and silver-silver chloride electrode system. During titration, an electronic voltmeter

is used to detect the change in potential between the two electrodes. The endpoint of the

titration is the instrument reading at which the greatest change in voltage has occurred for

a small and constant increment of silver nitrate added.

The sensitivity of the analysis can be adjusted depending on the amount of the sample

aliquot, concentration of AgNO3 solution, minimum volume that can be delivered by the

burette and the optimization of the program parameters in the autotitrator.

Samples are acidified with nitric acid to avoid carbonate precipitation. Bromide, iodide,

and sulfide are titrated along with the chloride. Orthophosphate and polyphosphate

interfere if present in concentrations greater than 250 and 25 mg/l, respectively.

Reference




Beaker, 150 ml capacity

Pipettes, 5 and 50 ml

Combined Ag-AgCl electrode


Autotitrator


0.1 N Silver nitrate, AgNO3, for high chloride concentration: Dissolve 16.987 g AgNO3,

AR, in one liter DD water and standardize or dilute 1 ampoule commercially available

0.1 N AgNO3 to 1 liter with DD water and standardize (see p. 126). Store in an amber

bottle.

0.01 N Silver nitrate, AgNO3, for low chloride concentration: Dissolve 1.699 g AgNO3,

AR, in one liter DD water and standardize. Alternatively, dilute 100 ml 0.1 N AgNO3 to

1 liter with DD water and standardize (see p. 126). Store in an amber bottle.

Chloride standard, 1000 mg/l Cl for 0.1 N AgNO3: Dissolve 1.65 g NaCl (dried at 110 ºC

for one hour) in one liter DD water or alternatively, prepare using commercially available

standards.

Chloride standard, 100 mg/l and 10 mg/l for 0.01 N AgNO3: Prepare by serial dilution

from 1000 mg/l AgNO3 or alternatively, prepare using commercially available standards.

50 % Nitric acid, HNO3: Add equal volumes of concentrated HNO3 and DD water.

Procedure

The various instruments that can be used in this determination differ in operating details;

follow manufacturer’s instructions. Make necessary mechanical adjustments.

Pipette 5 ml of sample (50 ml in case of low Cl) to a 150 ml beaker.

Add three drops of 50% HNO3 and stir.

Immerse the Ag electrode and burettes tip in the sample. Ensure that the junction hole of

the electrode is submerged in the sample by adding enough DD water.

Titrate the sample.

Calculation

mg/l = 35453VN/S

Where:

V = volume of silver nitrate used

N = normality of silver nitrate

S = sample aliquot in ml



Analyze check standard and control sample/standard prior to analysis of samples and

after every ten (10) samples, or with each batch of samples, whichever is less. The value

determined should be within 5% of the known or expected concentration. Otherwise, all

samples in the batch should be reanalyzed.






whole batch.

CHLORIDE (SPECTROPHOTOMETRIC WITH THIOCYANATE)

CAIR-BATAN, Indonesia

Scope

This test method covers the determination of chloride (Cl) in water samples at

concentrations by a spectrophotometric method using an UV-Vis spectrophotometer.

The applicable range of this test method is from 0.25 to 3.0 mg/l when using 460.0 nm

wavelength.

The sample solution is acidified with nitric acid and is evaporated on a water bath as

suppressant to arrest interference of sulfide.

Reference

Vogel (1961).


Spectrophotometer UV-Vis


Pipettes, 2 ml, 20 ml

Beaker, 50 ml

Reagent bottles, 500 and 250 ml

Filter paper, Whatman 42

Cuvette


Stock mercuric thiocyanate solution [Hg-(SCN)2] solution: Dissolve 4.17 g Hg-

thiocyanate in about 500 ml ethanol, dilute to 1000 ml with ethanol, mix and filter

through filter paper.

Ferric ammonium sulfate 0.25 M: Dissolve 12.05475 g Fe (NH4)(SO4)2.12H2O in 100 ml

9M HNO3 solution.

Stock chloride solution: Dissolve 1.6482 g NaCl, dried at 140°C in distilled water and

dilute to 1000 ml.

1.00 ml = 1.00 mg Cl

Procedure

Add 20 ml of the water sample to 2 ml Fe (NH4)(SO4)2.12H2O solution in a 25 ml

volumetric flask.

Add 2 ml Hg-thiocyanate solution and dilute to 25 ml with DD water and mix. Leave at

room temperature for about 10 minutes.

Note absorbance at 460 nm.

Calculation

Calculate for mg/l chloride by referring to the calibration curve

For diluted samples, calculate original concentration using:

mg/l Cl- = Concentration x dilution factor


DD water must be used in the preparation of samples/standards

Always include reagent blanks in the analysis

Add suppressant to blanks, standards and samples


the working range. Dilute if necessary

Absorbance values should be within the acceptable working standard range

Draw calibration curve using five standard concentrations, the correlation coefficient

should be r2 0.999

Spike and reanalyze after every five samples to check recovery. Recovery of the added

analyte should be between 90 and 110%. Otherwise, reanalyze the whole batch.

CHLORIDE (ION CHROMATOGRAPHY)

GESAL, El Salvador

Scope

This method covers the determination of chloride ion (Cl-) in filtered unacidified low-

salinity water samples by ion chromatography (IC).

The applicable range of this method is from 0.10 to 10.0 mg/l with a 100 l sample loop.

This range may be extended upward by dilution of an appropriate aliquot of sample.

A water sample is injected into a stream of carbonate-bicarbonate eluent and passed

through a series of ion exchangers. The anions of interest are separated on the basis of

their relative affinities for a low capacity, strongly basic anion exchanger (guard and

separator columns). The separated anions are passed through a suppressor column bathed

in continuously flowing regenerant solution (sulfuric acid solution). There, the separated

anions are converted to their highly conductive acid forms and the carbonate-bicarbonate

eluent is converted to weakly conductive carbonic acid.

The concentration of the separated anions in their acid forms is determined by

conductivity. They are identified on the basis of retention time as compared to standards.

Quantification is performed by correlating the peak area of the analyte obtained from the

sample solution to that obtained from the working standard solution.

Interferences can be divided into three different categories:

Direct chromatographic co-elution, where the analyte response is observed at very nearly

the same retention time as the target anion (i.e., relatively high concentrations of low-

molecular-weight organic acids)

Concentration dependent co-elution, which is observed when the response of higher than

typical concentrations of the neighbouring peak overlaps with the retention window of

the target anion; and,

Ionic displacement, where retention times may significantly shift due to the influence of

high ionic strength matrices (high mineral content or hardness) overloading the exchange

sites in the column and significantly shortening target analyte retention times.

References


Environment Federation (1995); American Society for Testing and Materials (1988);

Centro de Investigaciones Geotérmicas, Gerencia División de Recursos; Geotérmicos

(1993); Keith (1996).


Ion chromatograph

Anion separator column

Anion guard column

Membrane suppressor

Analytical balance

Volumetric flasks 1.0 to 1000.0 ml

Pipettes 1.0 to 50 ml

Membrane filter, 0.20 m

Test tubes

Syringes, plastic, disposable 0.1 and 10 ml


Reagent water: Use high quality water: distilled or deionized water of 18 megaohm-cm

resistivity containing no particles larger than 0.20 m

N2 gas for bubbling

Sodium chloride (NaCl), A.R.

Sodium bicarbonate (NaHCO3), A.R.

Sodium carbonate (Na2CO3) , A.R.

Sulfuric Acid (H2SO4), A.R.

Eluent solution. (2.8 mM NaHCO3-2.2 mM Na2CO3).

Dissolve 0.9409 g NaHCO3 and 0.9327g Na2CO3 in water and dilute to 4 l. Filter through

0.2 m.

Regenerant solution (H2SO4 0.025 N): Dilute 2.8 ml concentrated H2SO4 (sp. gr 1.84) to

4 l.

1000 mg/l Cl- stock solution: Stock standard solution may be purchased as a certified

solution or prepared as described below:

Dry sodium chloride (NaCl) for 1 hour at 600°C and cool in a desiccator. Weigh exactly

1.6484 g of dried salt and transfer to a 1000 ml volumetric flask. Dissolve in reagent

water and dilute with the same solvent. Filter to remove particles larger than 0.2 m and

store in plastic bottles in a refrigerator. This solution is stable for at least 1 month (verify

stability).

Working standard solutions (prepare fresh daily):

For calibration curve method: Prepare a series of working standards solutions (at least

four different concentrations) by diluting stock solution with reagent water.

Dilute samples: Prepare a calibration curve from 0.1 to 1.0 mg/l.

Concentrated samples: Prepare a calibration curve from 1.0 to 10 mg/l.

For a single standard calibration. Prepare one working standard solution with 50% of the

concentration for which the test procedure is designed (0.5 or 5 mg/l).

Procedure

Caution:

Clean the syringe. To prevent contamination of the sample, the syringe must be carefully

cleaned prior use. Often this is just a matter of rinsing the syringe at least twice with

water. The syringe should also be cleaned immediately after making an injection to

prevent dry sample residues.

Clean the system. The sample port should be rinsed after each standard or sample

injection by injecting water reagent.

Perform system equilibration. Set the chromatographic conditions listed below and let the

system to come to equilibrium1. For the best performance it is critical that baseline noise

be kept to a minimum. An equilibrated system will show a conductivity background

between 18 - 20 S.

Ion Chromatography working conditions

Eluent Pressure approx. 2.4 psi

Flow 2.8 ml/min

Regenerant Pressure approx. 3.5 psi

Flow: 1.9 ml/min

Pump Pressure 560 psi

Flow approx 2.5 ml/min

Detector Output range 2 30 s

Temperature compensation 1.7°C.

Loop 100 l

Run time approx.12 min

1 These conditions are guidelines. They should be optimized according to the instrument capabilities.

2 For low detection levels the sensitivity may be improved by using a lower scale setting.

Determine system blank by using water reagent as sample. This blank establishes the

baseline and confirms the lack of contamination in the system.

The sample port should be rinsed after each standard or sample injection by injecting

water reagent.

Calibration:

Determine chloride retention time by injecting one working standard solution.

Calibration curve. Inject and analyse at least four different concentrations of

analyte to bracket the sample concentration and construct a calibration curve by

plotting peak area against concentration.

Sample preparation:

Remove H2S from samples by bubbling with N2 (g) for 2 hours.

Filter through 0.2 m filter.

Sample reaction test: Transfer 2 ml of each sample to separate test tubes and add 3

ml of eluent solution. No precipitate or colour should be formed (otherwise the

sample cannot be processed).

Dilute samples if necessary. All samples must be within the working range, (avoid

overloading the ion-exchange and suppressor columns).

Sample analysis

Inject each sample. Inject enough sample to flush sample loop several times: for

0.100 ml sample loop inject at least 1 ml. After the conductivity signal has returned

to baseline, the next sample may be injected.

Calculation

Calculate the chloride ion concentration, in milligrams per litre, by referring to the

appropriate calibration curve. Alternatively, when response is shown to be linear, use the

following equation:

mg/lCl = AS/AR x CR x DF

Where:

AS = area of sample.

AR = area of reference solution (standard solution).

CR = concentration of standard in mg/l.

DF = dilution factor for those samples requiring dilution.


All solutions must be free of particles larger than 0.2 microns to avoid contamination and

plugging of the columns and flow system.

After every tenth field sample inject a calibration check standard in order to verify the

previously established calibration curve and confirm accurate analyte quantification for

the previous ten field samples analyzed. Acceptance limit should be within 1%.

End analysis of each batch by a check with the calibration check standard

Calculate the relative standard deviation (RSD) of the peak area for chloride in all

standard solutions. The RSD value should be 3.0% or less.

Separating performance of columns. When the analysis method is being used for the first

time with the equipment determine the plate number, plate height, tailing factor and

resolution of analyte peak.




whole batch.

FLUORIDE (ION SELECTIVE ELECTRODE-ISE)


Scope

This test method covers the determination of soluble fluoride ions in water using a

fluoride selective electrode.

Samples containing 0.25 to 50 mg/l can be analyzed by this method.

A fluoride selective electrode, a reference electrode and an ISE meter are used to

determine fluoride in a water sample by direct concentration readout. The fluoride

electrode consists of a lanthanum fluoride crystal that develops an electrode potential

corresponding to the level of fluoride ion in the solution.

Metal ions such as aluminum and iron (III) interfere with the fluoride determination by

forming complexes with fluoride ions. The buffer solution (TISAB series) contains a

complexing agent that preferentially complexes these metal ions.

References


Environment Federation (1995); American Society for Testing and Material (1994c, d)


Pipettor

Beaker, 50 ml

Pipette, 20 ml

Combined fluoride electrode


Ion selective meter

6-mm thick corkboard, heat barrier


Total ionic strength adjustor buffer, TISAB

TISAB II: To approximately 500 ml DD water in a 1 l beaker, add 57 ml glacial acetic

acid, 58 g NaCl and 4 g CDTA (1, 2-diaminocyclohexane N, N. N’, N’-tetraacetic

acid/commercially available as cyclohexylenedinitrilotetraacetic acid) or EDTA

(ethylenediaminetetraacetic acid). Stir to dissolve and cool in a bath. Immerse a

calibrated pH electrode in the solution, and slowly add approximately 5 M NaOH until

the pH is between 5.0-5.5. Cool to room temperature. Transfer to one litre volumetric

flask and dilute to mark with DD water. Commercially available prepared TISAB

solutions can also be used for this method.

TISAB III: Use same procedure and reagents as for TISAB II. For a 500 ml preparation,

add 385 ml glacial acetic acid, 290 g NaCl and 20 g CDTA to 150 ml DD water and

follow same steps as in the TISAB II preparation before finally diluting to the mark.

1000 mg/l F standard, stock: Dissolve 2.2101 g of anhydrous sodium fluoride, NaF, in

DD water and dilute to one liter. Commercially available standards can also be used.

100 mg/l F standard: Dilute 100 ml stock F solution to one liter with DD water.

Working standards (0.5, 5 and 50 mg/l): Transfer 0.5, 5 and 50 ml of 100 mg/l F into

separate 100 ml volumetric flasks and dilute to mark with DD water.

Procedure

Refer to the manufacturer’s instruction manual for proper operation of the meter.

Calibrate the equipment using the working standards. The meter must be recalibrated if

the sample concentration is outside the calibration range.

Transfer 20 ml sample to 50 ml beaker.

Add TISAB (1:1 for TISAB II or 1:10 for TISAB III) and immerse the fluoride electrode

in the sample while stirring continuously.

Allow the reading to stabilize and read the sample concentration directly from the meter.

Calculation

Report the fluoride content in mg/l.

For diluted samples, calculate original mg/l F using:

mg/l F = concentration x dilution factor


Analyze control standard/sample prior to analysis of samples.

Analyze the sample blank (in case of dilution) reagent blank, check standard and control

sample/standard after every five (5) samples, or with each batch of samples, whichever is

less. The check standard is chosen from one of the calibration standards, while the control

standard/sample is a separate preparation. The value determined should be within 5% of

the known or expected concentration. Otherwise, all samples in the batch should be

reanalyzed.


the working range, particularly in the upper range.

Check whether the slope of the calibration curve is within the recommended value (-54 to

-60 mV) before doing sample measurement.

Analyze duplicate samples. Acceptance limit for duplicate sample is 5%.


less) add a known amount of the F standard and reanalyze to confirm recovery. Recovery

of the added F should be between 95 and 105%. Otherwise, reanalyze the whole batch.


FLUORIDE (ION CHROMATOGRAPHY)

BRIUG, China

Scope

This test method covers the determination of fluoride in filtered un-acidified sample by

Ion Chromatography (IC).

The applicable range of this test method is from 0.5 to 20 mg/l when using the IC. This

range may be extended upward or downward by dilution of an appropriate aliquot of

sample or increasing the size of the sample loop.

A small volume of sample, 100 l is introduced into an ion chromatograph. The anions of

interest are separated and measured, using a system comprising a guard column, an

analytical column, a suppressor device, and a conductivity detector.

Interference can be caused by substances such as organic acids in high concentrations

with retention times that are similar to that of the fluoride anion and may overlap the

fluoride peak. Such interferences can be eliminated by means of sample dilution.

References

Dionex (1992), Keith (1996, EPA method 300.1).


Ion chromatograph with suppressor

Volumetric flasks, 50 ml and 100 ml

Pipettes, 1-20 ml

Reagent bottles, 50 ml and 100 ml

Volumetric flask, 1 l


Deionized water with a specific resistance of 17.8 megaohm – cm or greater.

Eluent: 5 mmole/l sodium borate: Thoroughly dissolve 1.90 g sodium borate, tetra

hydrate (MW 381.42 g/mole) in 700 ml deionized water (4.1) in a 1 l volumetric flask.

Dilute to a final volume of 1000 ml.

1000 mg/l F- stock solution

Commercial standard solution

Standard working solutions (0.5 to 20 mg/l F-)

Prepare at least four or five standards to bracket the expected F concentration of the

samples.

Procedure

Optimize the instrument according to its operation manual.


baseline is attained.

Inject the standard working solution and construct the standard calibration curve.

Flush the sampling system with each new sample.

Inject sample. Dilute when necessary so that the concentration falls within the standard

calibration curve.

During daily operation, it may be necessary to elute the polyvalent anions that

concentrate on the column with a 50-mole/l sodium borate solution (10×eluent strength)

for 10 minutes. After cleaning the column, equilibrate it for 20 minutes with the operating

eluent.

Calculation

Calculate F- content of the sample in mg/l from the calibration curve.

For diluted samples, calculate original mg/l using:

mg/l F- = concentrationdilution factor

The chromatogram working station can provide the content of F- directly.


Use the same quality deionized water to dilute the samples and to prepare the eluent and

working solution, otherwise check the blank concentration of the water.


Analyze the control standard /sample after a batch of samples. The control standard

should be prepared separately from the calibration standards. The value determined for

the control standard /sample should be within 5% of the known or expected

concentrations.

Analyze one set of the duplicate samples. Acceptance precision for duplicate samples is

10%




whole batch.

FLUORIDE (SPADNS SPECTROPHOTOMETRIC)

IAEA, Austria

Scope

The SPADNS spectrophotometric method is used for the determination of fluoride in

water samples with concentrations ranging from 0-1.4 mg/l. The method is preferable to

other spectrophotometric methods due to the instantaneous reaction between fluoride and

SPADNS reagent.

The SPADNS method is based on the reaction between fluoride and a red zirconium-dye

solution. The fluorides form a colorless complex with part of the zirconium, thus

bleaching the red color in proportion to the fluoride concentration. The reaction rate

between fluoride and zirconium ions is strongly influenced by the acidity of the reaction

mixture, and is increased proportionally to the increment of acid in the reagent.

The following substances in the given concentrations interfere with the determination of

fluoride, producing an error of 0.1 mg/l.

Interfering substance Concentration

Alkalinity (as CaCO3) 5000 mg/l

Aluminum 0.1 mg/l

Chloride 7000 mg/l

Iron 10 mg/l

Sodium Hexametaphosphate 1.0 mg/l

Phosphate, ortho 16 mg/l

Sulphate 200 mg/l

Interferences can be eliminated by distilling the sample from an acid solution.

A detailed description of the distillation procedure is given in American Public

Health Association, American Water Works Association (1992), page 4-60.

References

American Public Health Association, American Water Works Association,

Water (1992), Hach (1995).


UV/VIS Spectrophotometer

Cell with a minimal path of 1 cm

25 ml pipettes

5 ml transfer pipettes

Various volumetric flasks

Thermometers, - 10°C to 100°C


Deionized distilled water (DD water): Use deionized distilled water to prepare all

reagents and calibration standards.

Stock fluoride solution: Dissolve 221 mg anhydrous sodium fluoride, NaF in DD water

and dilute to 1000ml; this corresponds to 100 mg/l F. Alternatively, use commercially

available 1000 mg/l F standard solution and dilute it 10 times.

Standard fluoride solution: Dilute 100 ml stock fluoride solution to 1000 ml with DD

water; this correspond to 10 mg/l F

Working standards: Dilute 2.0, 5.0, 8.0, 10.0, and 14.0 ml of standard fluoride solution to

100 ml with DD water to obtain 0.2, 0.5, 0.8, 1.0 and 1.4 mg/l F.

Quality control sample: Prepare quality control sample, independently from the standards

used for calibration. It is recommended to use commercially available certified standard

solution, which should be appropriately diluted to a concentration within the range of

calibration curve.

SPADNS solution: Dissolve 958 mg SPADNS in DD water and dilute to 500ml.

Zirconyl-acid reagent: Dissolve 133 mg/l ZrOCl2 x 8 H2O in 25 ml DD water. Add 350 ml

conc. HCl and dilute to 500 ml with DD water.

Working reagent: Mix equal volumes of SPADNS solution and zirconyl-acid reagent.

This mixture is stable for at least 2 years. Alternatively use commercially available

SPADNS reagent

Sodium arsenate solution: Dissolve 5.0 g NaAsO2 and dilute to 1000 ml with DD water

Procedure

Carefully add 5 ml of SPADNS solution to 25 ml of distilled water (blank), to each

standard and sample, mix well, and measure after 1 min. Due to the high sensitivity of the

test, volume measurements should be performed very accurately and in order to avoid

contamination or dilution of the sample, all glassware should be absolutely clean and dry.

Set the photometer at 580 nm, transfer blank sample into cuvette, measure absorbance

and correct for background by pressing ’’ auto zero’’. Prior to measurements ensure that

the difference in the temperature between the water sample and the standard solution is

not more than (± 2°C). The best results are obtained with a temperature of about 20°C.

Record absorbance of standards, and plot the calibration curve. The correlation between

concentration and absorbance is linear up to 1.4 mg/l of fluoride.

Measure prepared samples. If the absorbance falls outside the range of the standard

curve, repeat the measurements using diluted sample.

Calculation

Determine unknown concentrations from plotted calibration curve.

If the sample was diluted, multiply results by a dilution factor;

mg/l F = concentration x dilution factor

Note: In order to calculate using the given formula, all the samples that require dilution

should be diluted to a final volume of 25 ml prior to addition of SPADNS reagent.

Quality Assurance/ Quality Control

Prior to analysis check for interference from aluminum. This is done by reading the

absorbance one minute after mixing with the SPADNS reagent, then again after 15 min.

An appreciable increase in concentration indicates the presence of aluminum as an

interference. To eliminate the effect of up to 3.0 mg/l Al, allow the sample to stand for

two hours before making the final reading.

To verify accuracy and quality of calibration standards begin the analysis with control

standard. If result obtained is not within ± 10 % of the certified value, prepare new

calibration standards and recalibrate the instrument.

Analyze check standard after every 10 samples or with each batch of samples, whichever

is less. This standard is chosen from one of the calibration standards. The check standard

should also be the last sample analyzed, in each run. The standard in which fluoride

concentration is closest to the actual fluoride content in the samples is recommended for

selection. The result obtained should be within 10% of the expected value.

Analyze one set of duplicate samples for every 10 samples or with each batch of samples,

whichever is less. The acceptance limits for duplicates is ± 10 %. To obtain accurate

results it is recommended that the test be repeated using the same glassware and sample

cells.

Sample concentration should be within the range of the calibration curve. Samples with

concentrations higher than the highest standard concentration should be diluted.

Whenever one interfering substance is present in sufficient quantity or if the extent of

interfering effect is in doubt, add a known amount of fluoride to the sample and repeat

the analysis. The increase in concentration should correspond to the concentration added

with deviation of ±10 %. If the presence of interfering substances is confirmed, samples

should be distilled using the procedure described in American Public Health Association,

American Water Works Association Water (1992), and pages 4-60. In some cases,

depending on the fluoride concentrations, it is possible to compensate for the interference

by diluting the sample, by using the standard addition method, or by adding an

appropriate amount of interfering substance to the standards.

If the sample contains residual chlorine, remove it by adding 0.05 ml NaAsO2 solution.




whole batch.

IRON (SPECTROPHOTOMETRIC WITH TPTZ)


Scope

Ferrous ion (Fe+2

) forms a violet complex with 2,4,6-tripyridyl-1, 3,5-triazine (TPTZ) at

pH 3.5 - 5.8. Ascorbic acid reduces ferric ion (Fe+3

) to ferrous ion and the solution is

buffered with sodium hydroxide and ammonium acetate after the addition of a small

amount of hydrochloric acid. The method is applicable to the determination of iron (Fe)

in water samples with concentrations ranging from 0.001 mg/l NH3 (using a 10 cm cell)

and above. Higher concentrations than about 2 mg/l can be determined following

appropriate dilutions.

The method is extremely sensitive to pH. If a standard or a sample shows a suspiciously

low absorbance check the pH of the solution with universal indicator paper. If pH outside

the range 3.5 - 5.8 either try to adjust it with an acid and/or a base solution or repeat the

sample preparation.

If an unusual color is observed add ascorbic acid only to the solution and measure the

absorbance. The value obtained (the color blank) is subtracted from the observed iron

concentration of the sample.

Iron is widespread in the environment and great caution needs be shown in the handling

of glass- and plastic ware. All new items should be acid-washed and others washed well

in deionized water each time.

References

Koroleff (1983)


Reagent bottles, 100 ml

Volumetric flasks, 100 ml, 50 ml and 25 ml (several)

Polyethylene bottles, 50 – 100 ml

Pipettes, 0.05 – 5 ml

pH meter

UV-Visible Spectrophotometer with appropriate size sample cells (1-10 cm)


6 N hydrochloric acid solution: Add 54 ml concentrated hydrochloric acid to 46 ml

deionized water.

2 N sodium hydroxide solution: Dissolve 8 g sodium hydroxide in 100 ml deionized

water (or dilute the 40% NaOH solution, used for sampling gas in steam, 5 times with

deionized water).

Ascorbic acid solution: Dissolve 7 g ascorbic acid in 100 ml deionized water. Store in a

refrigerator. Make up a new solution as soon as it starts turning yellow.

TPTZ solution: Add 0.5 ml concentrated hydrochloric acid to 0.08 g 2,4,6-tripyridyl-

1,3,5-triazine and dilute to 100 ml with deionized water. Store in a refrigerator.

Ammonium acetate solution: Dissolve 5 g ammonium acetate in 100 ml deionized water.

Iron intermediate standard solution. Dilute 1000 ppm iron stock solution to 10 ppm daily,

adding 0.120 ml 6 N hydrochloric acid solution to each 100 ml of solution.

Procedure

Prepare 0.1, 0.2 and 0.3 ppm iron standard solutions by dilution of the intermediate

standard solution, adding 0.120 ml 6 N hydrochloric to each 100 ml of solution.

Put deionized water in 25 ml volumetric flasks, add 0.030 ml 6 N hydrochloric acid, fill

one to the mark to serve as a blank, but add 0.100 ml of sample to each of to the others

(or a quantity that is expected to give a concentration of 0.1 - 0.3 ppm when diluted to 25

ml).

Place 25 ml aliquots of standards, blanks and diluted samples in 50 - 100 ml polyethelene

bottles.

Add 0.050 ml 2 N sodium hydroxide solution. Shake well.

Add 0.5 ml ascorbic acid solution, shake well and wait for at least 30 seconds.

Add 0.5 ml TPTZ solution and shake well.

Add 0.5 ml ammonium acetate solution and shake well.

Measure the absorbance of blanks, standards and samples at 595 nm.

Calculation

Read iron concentration in mg/l directly from the instrument or prepare standard

calibration curve to interpolate the sample concentration.

In case of dilution multiply measured concentration by dilution factor.


Analyze control standard/sample prior to analysis of samples.







the working range.




less) add a known amount of the Fe standard and reanalyze to confirm recovery.

Recovery of the added Fe should be between 95 and 105%. Otherwise, reanalyze the

whole batch.

LITHIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY)


Scope

This test method covers the determination of lithium (Li) in filtered acidified samples by


The applicable range of this test method is from 0.10 to 5.0 mg/l when using the 670.8

nm wavelength. This range may be extended upward by dilution of an appropriate

aliquot of sample.

Adding large excesses of an easily ionized element, such as potassium ion, controls

ionization interference.

References


Environment Federation (1995), American Society for Testing and Material (1995c).



Li hollow cathode lamp


Automatic dispenser

Pipettes, 1-25 ml

Erlenmeyer flasks, 50 ml, preferably plastic




50.00 g/l K as potassium chloride suppressant, KCl: Dissolve 95.84 g KCl, AR, in DD

water and dilute to 1000 ml.



replacing a cylinder with only 75 psig acetylene remaining.

Compressed air cleaned and dried by passing it through a suitable filter to remove oil,




50% HNO3: Mix equal volumes of DD water and concentrated HNO3.

1000 mg/l Li stock solution: Dissolve 5.323 g Li2CO3 in a minimum volume of 50%

HNO3. Add 10 ml conc. HNO3 and dilute with DD water to 1 liter. Alternatively, dilute

one ampoule of commercially available 1000 mg/l Li standard with acidified DD water.

Working standard solutions (0.1 to 5.0 mg/l): Prepare at least four standards to bracket


Standard blank solution: Add 1 ml KCl suppressant solution for every 20 ml acidified DD

water.

Procedure


Dilute samples with high Li so that the concentration falls within the standard calibration

curve. Pipette 20 ml of the sample into a 50 ml Erlenmeyer flask and add 1 ml KCl

suppressant. Mix well.


Aspirate each standard in turn into flame and record absorbance. Aspirate acidified DD

water between standards.

Aspirate samples and read the absorbance. Aspirate acidified DD water between samples.

Calculation

Calculate mg/l Li by referring to the calibration curve.

For diluted samples, calculate original mg/l Li using:

mg/l Li = concentration x dilution factor













concentration.












whole batch.


MAGNESIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY)


Scope

This test method covers the determination of magnesium (Mg) in filtered acidified

samples by atomic absorption spectrophotometry (AAS).

The applicable range of this test method is from 0.02 to 2.0 mg/l when using nitrous

oxide acetylene flame and 0.05 to 3.50 mg/l when using the air-acetylene flame at 285.2

nm wavelength. This range may be extended upward by dilution of an appropriate

aliquot.

Adding large excesses of an easily ionized element, such as potassium or lanthanum,

controls ionization interference.

References


Environment Federation (1995); American Society for Testing and Material (1995b)



Mg hollow cathode lamp


Automatic dispenser

Pipettes, 1-25 ml

Erlenmeyer flasks, 50 ml, preferably plastic




50 mg/l K as potassium chloride suppressant, KCl (for nitrous oxide-acetylene flame):

Dissolve 95.82 g KCl, AR, in DD water and dilute to 1000 ml.

50 g/l La as lanthanum oxide, La2O3: Wet 58.7 g La2O3, AR, in DD water. Add slowly

250 ml of concentrated HCl to the mixture. When dissolved, dilute to 1000 ml with DD

water.



replacing a cylinder which has only 75 psig acetylene remaining.

Nitrous oxide, at least medical grade



Conc. HNO3


1000 mg/l Mg stock solution: Dissolve 1.658 g magnesium oxide, MgO, in DD water and

dilute to 1 liter. Alternatively, dilute one ampoule of commercially available 1000 mg/l

Mg standard with acidified DD water.

Working standard solutions (0.02 to 2.0 mg/l Mg for nitrous oxide-acetylene flame, 0.05

to 3.50 mg/l for air-acetylene flame)

Prepare at least four standards to bracket the expected concentration of the samples.

Standard blank solution: Add 1 ml suppressant solution for every 20 ml acidified DD

water.

Procedure


Dilute samples with high Mg so that the concentration falls within the standard

calibration curve. Transfer 20 ml of the sample to a 50 ml Erlenmeyer flask and add 1 ml





Aspirate samples to obtain the absorbance. Aspirate acidified DD water between each

two samples.

Calculation

Calculate mg/l Mg by referring to the calibration curve.

For diluted samples, calculate original mg/l Mg using:

mg/l Mg = concentration x dilution factor













concentration.












whole batch.


MAGNESIUM (ION CHROMATOGRAPHY)

BRIUG, China

Scope

This test method covers the determination of magnesium in filtered acidified samples by



range may extended upward or downward by dilution of an appropriate aliquot of sample

or enlarging the sample loop.

A small volume of sample, 100 l, is introduced into an ion chromatograph. The anions

of interest are separated and measured, using a system comprising a guard column, an


Interference can be caused by substances such as potassium and calcium in high

concentrations overlapping the Mg peak. Sample dilution can be used to solve

interference problems.

Reference

Dionex (1992), Keith (1996, EPA Method 300.7)

Material and Equipment



Pipettes, 1-20 ml


Volumetric flasks, 1000 ml


Deionized water with a specific resistance of 17.8 megohm – cm or greater

Eluent : 20 mmole/l methanesulfonic acid : Pipette 1.3 ml methanesulfonic acid into a 1 l

volumetric flask , dilute to 1000 ml using water (4.1), degas the eluent .

1000 mg/l Mg2+

element stock solution: Commercial standard solution

Standard solution (0.5 to 20 mg/l Mg2+

): Prepare at least four standards to bracket the

expected Mg concentrations of the samples

Procedure



Optimize the instrument according to the instrument’s operation manual.



Dilute samples when necessary so that the concentration of the element falls within the

standard calibration curve.

Calculation

Calculate mg/l by referring to the calibration curve.

For diluted samples, calculate original mg/l using :

mg/l Mg2+

=concentrationdilution factor

The chromatogram working station can provide the content of Mg2+

directly.



working solution, otherwise, check the blank concentration of the water. Check that the

first order linearity of the standard calibration curve has r2 0.999.

Analyze the control standard/sample after a batch of samples. A control standard should

be prepared separately from the calibration standards. The value determined for the

control standard/sample should be within 5% of the known or expected concentrations.

Analyze one set of duplicate samples. Acceptance precision for duplicate samples is

10%.



Recovery of the added metal should be between 95 and 105%. Otherwise reanalyze the

whole batch.

PH (ELECTROMETRIC)


Scope

This method covers the determination of pH in water by electrometric measurement using

the glass electrode as sensor. The sample measurement is made under strictly controlled

laboratory conditions.

Fresh and air-free samples should be analyzed to avoid interference due to carbon dioxide

absorption from the atmosphere.

The true pH of an aqueous solution is affected by the temperature, which can be corrected

using an automatic temperature compensator, or it can be manually compensated for in

other instruments.

Reference


Pollution Control Federation (1995).


pH/mV meter

pH electrode


Beakers, 150 ml.


pH 6.86 reference buffer solution: Oven-dry about 5 g each of potassium dihydrogen

phosphate (KH2PO4) and disodium hydrogen phosphate (Na2HPO4) for two hours at

130ºC. Dissolve 3.39 g of KH2PO4 and 3.53 g of Na2HPO4 in DD water and dilute to one

liter. Alternatively, use calibrated commercially available pH 7.00 buffer solution.

pH 4.00 reference buffer solution: Dissolve 10.12 g of oven-dried (2 hours at 110ºC)

potassium hydrogen phthalate (KC8H5O4) in DD water and dilute to one liter.

Alternatively, use calibrated commercially available pH 4.00 buffer solution.

Procedure

Standardize the pH/mV meter according to the instrument’s operating manual using pH

4.00 and pH 6.86 or pH 7.00 buffer solutions.

Transfer about 50 ml sample into a 150 ml beaker. Immerse pH electrode in the sample.

Ensure that the junction hole of the electrode is submerged.

Establish equilibrium between electrodes and sample by stirring the sample to ensure

homogeneity. Stir gently to minimize carbon dioxide entrapment.

Record the pH and temperature of the sample. Report the pH values and temperature of

the measurement to the nearest 0.1 pH unit and 1ºC, respectively.


Calibrate the pH electrode using at least two (2) buffers, whose pH should bracket the

expected pH of the sample. Slope should be between 0.95 and1.05.

The standard mV value for pH 7.0 buffer solution at 25ºC should be between 0 ± 30 mV.

For pH 4.0 buffer solution, the mV value should be approximately 160 mV greater than

the pH 7.0 mill volt reading.

Perform buffer check after every five (5) samples. Value determined should be 0.1 pH

unit of the theoretical value. Otherwise, recalibrate the pH meter.

POTASSIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY)


Scope

This test method covers the determination of potassium (K) in filtered acidified samples

by atomic absorption spectrophotometry (AAS).

The applicable range of this test method is from 0.40 to 1.50 mg/l at 766.5 nm, 1.10 to

4.40 mg/l at 769.9 nm, and 150 to 580 mg/l at 404.4 nm wavelength. These ranges may

be extended upward either by dilution of an appropriate aliquot of sample or rotating the

burner head.

Adding large excesses of an easily ionized element, such as cesium ion, controls


References


Environment Federation (1995); American Society for Testing and Material (1995d).



K hollow cathode lamp


Automatic dispenser

Pipettes, 1-25 ml


Reagent bottles, 1 liter and 250 ml, plastic



50 g/l Cs as cesium chloride suppressant, CsCl: Dissolve 63.66 g CsCl, AR, in DD water

and dilute to 1000 ml.

Acetylene gas with purity of at least 99.5 vol %

Acetone, which is always present in acetylene cylinders, can be prevented from entering

and damaging the burner system by replacing a cylinder when only 75 psig acetylene

remain.




1000 mg/l K stock solution: Dry about 2.5 g KCl to constant weight at 105ºC. Dissolve

1.907 g KCl in DD water and dilute to 1 liter. Alternatively, dilute one ampoule of

commercially available 1000 mg/l K standard with acidified DD water.

Working standard solutions (0.40-1.50, 1.10-4.40 or 150-580 mg/l K): Prepare at least

four standards to bracket the expected concentration of the samples at the appropriate

wavelength.

Standard blank solution: Add 1 ml CsCl suppressant solution for every 20 ml acidified

DD water.

Procedure


Dilute samples with high K so that the concentration falls within the standard calibration

curve. Pipette 20 ml of the sample to a 50 ml Erlenmeyer flask and add 1 ml CsCl



Aspirate each standard in turn into the flame and record absorbance. Aspirate acidified

DD water between standards.


Calculation

Calculate mg/l K by referring to the calibration curve.

For diluted samples, calculate original mg/l K using:

mg/l K = concentration x dilution factor









Check that the first order linearity of the standard calibration curve has r20.999.

Analyze the blank and control sample/standard before analyzing samples. The control

standard is a separate preparation from the calibration standards. The determined value of

the control sample/standard should be within 5% of the known or expected

concentration.






from one of the calibration standards, while the control sample/standard is a separate

preparation. The determined value should be within 5% of the known or expected





whole batch.


POTASSIUM (ION CHROMATOGRAPHY)

BRIUG, China

Scope

This test method covers the determination of potassium in filtered acidified sample by




sample or enlarging the sample loop.

A small volume of sample, 100 ul is introduced into an ion chromatograph. The anions of



Interference can be caused by substances such as sodium, ammonium and magnesium in

high concentrations overlapping the K peak. Sample dilution can be used to solve

interference problems.

Reference

Dionex (1992), Keith (1996, EPA Method 300,7).




Pipettes, 1-20 ml





Eluent: 20 mmole/l methanesulfonic acid: Pipette 1.3 ml methanesulfonic acid into a 1 l

volumetric flask, dilute to 1000 ml using water (4.1), degas the eluent.

1000 mg/l K+

element stock solution: Commercial standard solution

Standard solution (0.5 to 20 mg/l K+): Prepare at least four standards to bracket the

expected K concentrations of the samples

Procedure








Calculation



mg/l K+=concentrationdilution factor

The chromatogram working station can provide the content of K+ directly.





Analyze the control sample/standard after a batch of samples. A control standard should


control sample/standard should be within 5% of the known or expected concentrations.

Analyze one set of duplicate samples. Acceptance limit for duplicate samples is 10%.


less) add a known amount of potassium and reanalyze to confirm recovery. Recovery of

the added potassium should be between 95 and 105%. Otherwise, reanalyze the whole

batch.

POTASSIUM (ATOMIC EMISSION SPECTROSCOPY (AES)


Scope

This test method covers the determination of potassium (K+)

in filtered acidified samples

by Atomic Emission Spectrophotometry (AES) using an Atomic Absorption

Spectrophotometer (AAS)

The applicable range of this test method is from 0.25 to 2.0 mg/l using the 766,5 nm

wavelength.

Lanthanum oxide is added as suppressant to arrest ionization interference.

References

American Public Health Association Water Works Association and Water

Pollution Control Federation (1985); Rodier (1975).


Atomic absorption spectrophotometer.

Volumetric flasks, 25 and 50 ml.

Pipettes, 1-25 ml

Erlenmeyer flasks, 50 ml.

Reagent bottles, 500 and 250 ml, preferably plastic

Filter, with particle retention of 0,45 m.

Air compressor


La2O3 solution, 5000 mg/l, wet 5.8637 g La2O3 in 2% HNO3 solution, and dilute to 1000

ml using DD water.

Acetylene gas.

Compressed air.

1000 mg/l K stock standard solution: Dissolve 1.907 g KCl in 1% HNO3 solution, dilute

to 1 l with DD water.

Working standard solution (0.25 to 2.0 mg/l K): Prepare five standards to bracket the

expected concentration of the samples.

Standard blank solution: Add 2.5 ml La2O3 suppressant for every 25 ml DD water.

Procedure


Dilute samples with high K so that concentration falls within the standard calibration

curve.

Aspirate the reagent blank to zero the instrument

Aspirate each standard in turn into flame and read the emission

Aspirate the samples between standards and read the emission.

Calculation

Calculate mg/l K by referring to the calibration curve.

For diluted samples, calculate original mg/l K using

mg/l K= concentration x dilution factor


DD water must be used in the preparation of samples/standards.

Always include reagent blanks in the analysis.

Add suppressant (La2O3 solution) to blanks, standards and samples.



Emission values should be within the acceptable standard working range, as specified in

the manufacturer’s manual.

Check that the first order linearity of the standard calibration curve has r2 0.999. The

slope has to be checked for every 10 (ten) measurements together with the blank and

standard solution.

Analyze the blank and the calibration standard before analyzing samples. The value

determined should be within 5% of the known or expected concentrations.

Spike every 3 (three) samples; the recovery should be between 93.5 - 104.5 %.

SILICA-TOTAL (SPECTROPHOTOMETRIC WITH AMMONIUM-

MOLYBDATE)


Scope

This test method covers the determination of silica in natural water and geothermal brine

by the molybdosilicate method.

The method includes alkaline digestion to break down polymeric silica. Ammonium

molybdate at pH approximately 1.2 reacts with monomeric silica and any phosphate

present to produce heteropoly acids. Oxalic acid is added to destroy the

molybdophosphoric acid but not the molybdosilicic acid. The intensity of yellow color is

proportional to the concentration of “molybdate-reactive silica”, and is analyzed at 410

nm.

The method is applicable to acidified samples with silica concentrations in the range 10-

800 mg/l. Higher concentrations can be determined after appropriate dilutions.

Color and turbidity will interfere if not removed by filtration or dilution.

Phosphate, sulfide and ferric ion interfere in the color reaction. Addition of oxalic acid

eliminates phosphate and ferric ion interferences. In cases of high sulfide, samples

require bubbling. Sulfide may alternatively be removed by adding iodine and then

thiosulfate to remove excess iodine.

Avoid using glassware and reagents with significant amounts of silica to minimize

contamination.

References

Ellis and Mahon (1977); Giggenbach and Goguel (1989)


UV-visible Spectrophotometer

Water Bath

Volumetric flask, 100 ml, plastic with screw cap

Pipettes, 2 to 5 ml

Reagent dispenser or pipettor


10% (w/v) Ammonium molybdate, (NH4)6Mo7O24H2O: Dissolve 10 g

(NH4)6Mo7O24H2O in DD water then dilute to 100 ml. Adjust to pH 7 with NaOH. Store

in plastic bottle.

6 N HCl: Mix equal volumes of concentrated HCl and DD water.

6 N NaOH: Dissolve 24 g NaOH pellets in DD water and dilute to 100 ml.

15% (w/v) oxalic acid, C2H2O4H2O: Dissolve 15 g C2H2O4H2O in DD water and dilute to

100 ml.

Absolute ethanol C2H6O: 1% (w/v) phenolphthalein indicator: Dissolve 1 g of

phenolphthalein powder, AR, in 150 ml ethanol and dilute to 100 ml with DD water.

Store in plastic bottle.

1,000 mg/l silicon stock solution: Dilute one ampoule commercially available 1000 mg/l

Si standard to 1 liter with DD water.

Working standard solutions:Low concentration range (10 to 100 mg/l Si equivalent to

21.4 to 214 mg/l SiO2). Prepare at least four standards to bracket the expected


High concentration range (100 to 800 mg/l Si equivalent to 214 to 1712 mg/l SiO2):


Procedure

Shake or stir sample. When working in the high Si concentration range, pipette 2 ml

standard solutions and samples into individual 100-ml volumetric flasks. In the case of

low concentration range, pipette 10 or 20 ml standard solutions and samples into 100-ml

volumetric flasks.

Prepare a reagent blank by treating 2, 10 or 20 ml aliquot of DD water, as required.

Add 2 to 3 drops of phenolphthalein indicator.

Add 0.5 ml 6 N NaOH and rinse sides of flask with DD water.

Cover with cap and heat in water bath for 45 minutes to 1 hour at 80-90C.

Remove from water bath and cool.

Add 2 ml 6 N HCl and 5 ml ammonium molybdate solution. Shake and allow to stand for

15 minutes.

Add 2 ml 15% oxalic acid, dilute to mark with DD water and shake.

Measure the absorbance of the samples at 410 nm against the reagent blank.

Calculation

Read silica concentration in mg/l directly from the instrument or prepare a standard

calibration curve to read the sample concentration. Check that the concentration is

expressed as SiO2 not Si.


mg/l SiO2 = concentration x dilution factor



Standard concentrations should bracket the sample concentrations and be within the

working range. Dilute samples if necessary.







Analyze the reagent blank and control sample/standard before analyzing samples. The



concentration.

Only ten (10) samples should be analyzed per batch run.




from one of the calibration standards. The values determined should be within 5% of the


reanalyzed.

To one sample out of every five (or with each batch of samples, whichever is less) add a

known amount of the standard and reanalyze to confirm recovery. Recovery of standard

should be between 95 and 105%. Otherwise, reanalyze the whole batch.


SILICA (SPECTROPHOTOMETRIC WITH AMMONIUMMOLYBDATE AND

HETEROPOLY BLUE)


Scope

This test method covers the determination of low silica levels in geothermal fluids.

Ammonium molybdate at pH approximately 1.2 reacts with silica and any phosphate

present to produce heteropoly acids. Oxalic acid is added to destroy the

molybdophosphoric acid but not the molybdosilicic acid. The yellow molybdosilicic acid

is reduced by means of aminonaphtholsulfonic acid to heteropoly blue, and is analyzed at

815 nm.

The range of this method is from 0.02 to 1.00 mg/l of silica.

Color and turbidity will interfere if not removed by filtration or dilution.

Phosphate, sulfide and ferric ion interfere in the color reaction. Addition of oxalic acid

eliminates phosphate and ferric ion interferences. Sample requires bubbling to eliminate

H2S interference. Sulfide may alternatively be removed by adding iodine and then

thiosulfate to remove excess iodine.

References


Pollution Control Federation (1995); American Society for Testing and Material (1995a).


UV-visible Spectrophotometer

Volumetric flask, 100 ml capacity, plastic with screw cap

Pipettes, 5 to 20 ml

Reagent dispenser or pipettor


10% (w/v) Ammonium molybdate (NH4)6Mo7O24H2O: Dissolve 10 g (NH4)6Mo7O24H2O

in DD water then dilute to 100 ml. Adjust to pH 7 by adding NaOH. Store in a plastic

bottle.

6 N HCl: Mix equal volumes of concentrated HCl and DD water.

Amino-naphtol sulfonic acid (ANSA) solution: Dissolve 1 g Na2SO3 and 30 g NaHSO3 in

about 100 ml DD water. Dissolve 0.50 g ANSA in this solution and dilute to 200 ml.

Store in a plastic reagent bottle.

1000 mg/l silicon stock solution: Dilute one commercially available ampoule, 1000 mg/l

Si standard to 1 liter with DD water.

100 mg/l silicon stock solution: Dilute 10 ml 1000 mg/l Si standard to 100 ml with DD

water.

Working standard solutions (0.10 to 1.0 mg/l Si equivalent to 0.21 to 2.14 mg/l SiO2):


Procedure

Transfer about 100 ml of sample into a beaker. Bubble N2 gas into the sample for 15 to

30 minutes to remove H2S.

Pipette 50 ml standard solutions and samples into individual 100 ml volumetric flasks.

Prepare a reagent blank by treating a 50 ml aliquot of DD water.

Add in rapid succession 1 ml 6 N HCl and 2 ml 10% ammonium molybdate. Mix and

allow to stand for exactly five minutes.

Add 1.5 ml 10% oxalic acid and mix well.

After one minute, add 2 ml ANSA. Mix and allow to stand for 10 minutes.


Calculation

Read silica concentration in mg/l directly from the instrument or prepare standard

calibration curve to read the sample concentration from. Check that the concentration is

expressed as SiO2 and not Si.














concentration.






reanalyzed.





SILICA (ATOMIC ABSORPTION SPECTROPHOTOMETRY)

GESAL, El Salvador

Scope

This test method covers the determination of silica usually present in geothermal waters,

in filtered acidified (pH 1.2-1.5) samples by atomic absorption spectrophotometry (AAS).

The applicable range of this method is from 50 to 500 mg/l when using the 250.7 nm

wavelength.

In flame atomic absorption spectrophotometry, a sample is aspirated into a flame and

atomized. A light beam is directed through the flame, into a monochromator, and into a

detector with which the amount of light absorbed by the atomized element in the flame is

measured. For some metals, atomic absorption exhibits superior sensitivity over flame

emission. Because each metal has its own characteristic absorption wavelength, a source

lamp composed of that element is used; this makes the method relatively free from

spectral or radiation interferences. The amount of energy at the characteristic wavelength

absorbed in the flame is proportional to the concentration of the element in the sample

over a limited concentration range.

Severe depression of silicon absorbance has been observed in the presence of

hydrofluoric acid, boric acid and potassium at significant levels (1%). The effect is

minimized by adjusting the flame to neutral stoichiometry (red cone 0.5-1 cm high), with

consequent loss of sensitivity.

References


Environment Federation (1995); Skoog and Leary (1994).



Silicon hollow cathode lamp

Volumetric flasks, 50, 100 and 200 ml

Pipettes 2-10 ml

500 ml plastic flasks

Filter paper, Whatman No. 42

Pumping system to introduce and automatically dilute sample (SIPS)




Acetone is always present in acetylene cylinders. Serious damage in the burner system

can be prevented by replacing a cylinder when only 80 psig acetylene remain.

Air compressor is cleaned and dried by passing the gas through a suitable filter to remove

oil, water, and other foreign substances.

Nitrous oxide gas with purity of at least 99.2 %.

Fit nitrous oxide cylinder with a special non-freezable regulator or wrap a heating coil

around an ordinary regulator to prevent flashback at the burner caused by a reduction in

nitrous oxide flow through a frozen regulator.

Acidified DD water. Add 10 ml concentrated nitric acid, HNO3, for every 500 ml DD

water.

Acidified standard silica stock solution, 1000 mg/l: Silica stock solution may be

purchased as a certified solution or prepared as described below: Fuse 0.2139 g of silicon

dioxide with 2 g of sodium carbonate in a platinum crucible. Dissolve with DD water and

transfer to a 100 ml volumetric flask and dilute to 1 liter with DD acidified water.

Working standard solutions: Prepare at least four standards in the expected concentration

range of the sample

Standard blank solution: Add 2 ml concentrated HNO3, dilute to 100 ml with acidified

DD water.

Procedure

Optimize the instrument according to instrument’s operating manual. (Follow the safety

guidelines specified by the equipment manufacturer).

Wash SIPS for 15 minutes with DD water to eliminate any type of contaminants in the

whole pumping system.

Verify the sensitivity and stability of the signal using the highest concentration standard

prepared for the calibration curve, (e.g. for a wavelength of 250.7 nm one 240 mg/l

standard must read 0.2 of absorbance).

When stable, proceed to set zero absorbance and then prepare the calibration curve

manually with the help of the sample dilution system i.e. read the blank and then the

standards from lower to higher concentrations and make the program subtract the blank

absorbance from each standard until a linear calibration curve is obtained. If there is an

auto dilution system program follow the preparation of the calibration curve is succeeded

by a washing step.

If there is no auto dilution system, prepare standards of 100, 200, 300, 400 and 500 mg/l

and the calibration curve.

When the calibration curve has been prepared read the standard absorbance.

Analyze one control sample/standard and fourteen samples. Rinse the system after every

sample reading.

If the concentration of a sample is out of the range of the calibration curve, introduce into

the auto dilution program a suitable dilution factor. If an auto dilution system is not

available make suitable dilutions.

Recalibrate the system after fourteen samples.

Calculations

Calculate mg/l SiO2 by referring to the calibration curve,

mg/l SiO2 = silicon concentration in mg/l x 2.14

For diluted samples, calculate original mg/l SiO2 using:

mg/l SiO2 = silicon concentration x 2.14 x dilution factor

Where 2.14 is gravimetric factor to convert silicon to silica

Quality control

All the samples must be filtered and acidified previously to keep the analytes in solution.





manufacturer's manual.

Check that the precision of the standard calibration curve is < 0.1%.

Analyze the control sample/standard before analyzing samples. The control standard is a

separate preparation from the calibration standards. The percent difference between the

concentration value determined by the equipment and the theoretical one must be within

5%.

Recalibrate the equipment after every fourteen samples. Analyze the control

sample/standard after recalibration verifying the percent difference between the

theoretical and analyzed values. If the results were out of range, a new calibration must

be carried out.




SILICA, TOTAL (ICP– ATOMIC EMISSION SPECTROMETRY)

DMGM, Malaysia

Scope

Total silica in filtered and acidified water samples is determined by this method.

The applicable range of this method is 0.005 – 250 mg/l using the emission line at

251.611 nm.

Main sources of interferences are: spectral interferences, non-spectral interferences and

chemical interferences

Spectral interferences can be minimized by selecting the emission lines with the smallest

line overlaps, while non-spectral interferences and chemical interferences can be

minimized by matrix matching the standards to the samples.

References

ICP–AES Manufacturer’s Manual: American Public Health Association, American Water

Works Association and Water Pollution Control Federation (1989).


Inductively coupled plasma – atomic emission spectrophotometer.

Volumetric flasks, 1000 ml and 100 ml.

Pipettes, 2 – 20 ml

Polyethylene test tubes

Reagent bottles, 1 l and 250 ml, plastic.



Deionized water

Argon gas with purity of at least 99.995%

1000 mg/l Si stock solution: Dissolve 10.1190 g sodium metasilicate; Na2SiO3.9H2O in

700 ml deionized water containing 50 ml concentrated HNO3. Transfer the solution to a 1

l volumetric flask and dilute to mark with deionized water. Store in a plastic bottle.

100 mg/l Si stock solution: Dilute 10 ml of 1000 mg/l Si stock solution to 100 ml with

5% HNO3 solution. Store in a plastic bottle.

Working standard solutions: Prepare two standards to bracket the expected concentration

of the sample. One standard per order of magnitude is sufficient, for example 5 mg/l and

50 mg/l. Dilute to volume with 1% HNO3.

Standard blank solution: Prepare 1% HNO3 solution.

Procedure

Optimize the instrument and make measurements according to the manufacturer’s

instruction manual.

Transfer a suitable amount of well-mixed nitric acid preserved sample solution into a

small polyethylene test-tube.

Run blank and working standards and obtain readings.

Run samples and obtain readings.

Calculation

Calculate mg/l Si from the calibration curve.

To report the value as mg/l SiO2 multiply mg/l Si with 2.1393.


Run a sample with known amounts of SiO2 or a certified reference standard. Prepare the

sample with the same acid matrix.

Recheck the standards after running 10 samples to determine if significant instrument

drift has occurred. Recalibrate the instrument if the results are not within + 5% of the

expected values.

Test for matrix interference by spiking the test sample with known amounts of silica.

Recovery of the addition should be between 95% and 105%.

SODIUM AND POTASSIUM (ICP-ATOMIC EMISSION SPECTROMETRY)

IAEA Isotope Hydrology Lab, Austria

Scope

The ICP-AES method is used to analyze sodium and potassium in acidified water

samples with concentrations ranging from 5-100 mg/l for sodium and from 1-20 mg/l for

potassium. Water samples with higher concentrations should be diluted appropriately.

The sample is introduced into the instrument as a stream of liquid that is converted inside

the instrument into an aerosol and then transported to the plasma where it is vaporized,

atomized, and ionized. The excited atoms and ions emit their characteristic radiation,

which is collected and sorted by wavelength. The radiation is detected and turned into

electronic signals that are converted into concentrations.

The sample matrix can cause physical interferences and total salt concentrations of more

than 0.5 % might cause ionization and viscosity interferences.

References


Environment Federation (1992); Boss and Fredeen (1993).


Perkin Elmer PLASMA 400

Perkin Elmer AS 90 Autosampler

PC: Digital DEC pc Lpv 433dx with Perkin Elmer software

Millipore equipment for filtration and 0.45um filters

Volumetric flasks

Pipettes and micropipettes, 1-50 ml

Vials, 50 ml for auto-sampler


Deionized distilled water (DD water): Use deionized distilled water to prepare all

reagents and calibration standards.

Hydrocloric acid, HCl, conc., and diluted 1:1 with DD water

Nitric acid, HNO3, conc., and diluted 1:1 with DD water

Stock sodium solution: Dissolve 2.542 g NaCl dried at 140°C and dilute in 1000 ml DD

water; this corresponds to 1.00 mg/ 1.0 ml. Alternatively, use a commercially available

1000 mg/l sodium standard solution.

Stock potassium solution: Dissolve 1.907 g KCl dried at 110°C and dilute to 1000 ml

with DD water; this corresponds to 1.00 mg/ 1.0 ml. Alternatively, use a commercially

available 1000 mg/l sodium standard solution.

Standard potassium solution: Dilute 10 ml stock potassium solution to 100 ml with DD

water; this corresponds to 100 mg/l K

Mixed working standards Na/K: Prepare mixed calibration standards by combining

appropriate volume of sodium stock solution with potassium standard solution in a 200

ml volumetric flask. (See Table). Acidify with 0.2 ml conc. HNO3, and dilute to volume

with DD water.

Na stock

solution, ml

K standard

solution, ml

Final

volume, ml

Na

concentration,

mg/l

K concentration,

mg/l

20 40 200 100 20

10 20 200 50 10

5 10 200 25 5

2 4 200 10 2

1 2 200 5 1

Store mixed standard solutions in unused polyethylene bottles.

Method blank: Prepare method blank by adding 0.1 ml of conc. HNO3 to 100 ml of DD

water.

Calibration blank: Prepare a sufficient quantity of calibration blank in order to flush the

system between standards and samples. Dilute 2ml 1:1 HNO3 and 10 ml 1:1 HCl to 100

ml DD water.

Quality control sample: Prepare quality control sample independent of the standards used

for calibration. If possible, use certified reference materials as laboratory control

standards, e.g., National Institute of Standards and Technology ((NIST) Standard

Reference Material 1643d is commonly used for water analysis

Procedure

Filter samples through the 0.45 m Millipore filter and dilute if necessary. As the usual

concentration of sodium and potassium in geothermal waters is relatively high, dilute the

samples to a conductivity of about 500-1000 S to prevent eventual non-spectral

interferences or buildup of salts at the tip of the nebulizer,

Transfer samples to the 50 ml vials and ensure that the temperatures of samples and

standards are similar and the pH is below 2.

Carry out measurements at the selected wavelengths of 766.490 nm for potassium and

589.592 nm for sodium. Other operating conditions such as: PMT voltages, background

correction, argon flow rates, RF power, etc., depend on the model of the ICP instrument;

therefore for routine analysis refer to the manufacturer’s instructions.

Calibrate the instrument using working standards and blank. Aspirate each standard or

blank for 20 sec. after reaching the plasma before beginning signal integration. Rinse

with calibration blank for at least 60 sec. between each standard to eliminate any traces of

the previous standard. During sample analysis continue to rinse with calibration blank for

at least 60 sec. between each sample.

Calculation

The concentration of samples is calculated using computer software supplied by the

instrument manufacturer.

If the sample was diluted, multiply results by a dilution factor.

mg/l Na = concentration x dilution factor


Analyze quality control standard prior to analysis of samples, to verify accuracy and

stability of the calibration standards. If the result obtained is not within ± 5 % of the

certified value, prepare new calibration standards and recalibrate the instrument.

Analyze reagent blank and check standard after every 10 samples or with each batch of

samples to determine if instrument drift has occurred. This standard is chosen from one

of the calibration standards. The check standard should also be the last sample analyzed

in each run. The value obtained should be within ± 5 % of the expected concentration,

otherwise all samples analyzed after the last acceptable value must be reanalyzed.

Analyze samples in duplicate. Acceptable limit for duplicates is ± 5 %.

Sample concentration should be within the range of the calibration curve. Samples with

concentrations higher than the highest standard concentration should be diluted.

To verify result and exclude matrix interferences dilute every 10th

sample and every one

with a high salt content. As mentioned before, interferences caused by high salt content

can be solved by diluting the samples to a conductivity of about 500-1000 S. The result

obtained for different dilutions should agree within ± 5 %. If the agreement is not

acceptable, samples should be further diluted until the values determined for two

different dilutions agree to within ± 5 %.

SODIUM (ATOMIC ABSORPTION SPECTROPHOTOMETRY)


Scope

This test method covers the determination of sodium (Na) in filtered acidified samples by



nm wavelength. This range may be extended upward either by dilution of an appropriate

aliquot of sample, or using the less sensitive 330.2 nm wavelength, or rotating the burner

head.

Adding large excesses of an easily ionized element, such as potassium, controls


References


Pollution Control Federation (1995); American Society for Testing and Material (1995e).



Na hollow cathode lamp


Automatic dispenser

Pipettes, 1-25 ml


Reagent bottles, 1 liter and 250 ml, plastic



50 g/l K as potassium chloride suppressant, KCl: Dissolve 95.82 g KCl, AR, in DD water

and dilute to 1000 ml.


Acetone, which is always present in acetylene cylinders, can be prevented from entering

and damaging the burner system by replacing a cylinder when only 75 psig acetylene

remain.




1000 mg/l Na stock solution: Dry about 3 g NaCl to constant weight at 105ºC. Dissolve

2.542 g NaCl in DD water and dilute to 1 liter. Alternatively, dilute one ampoule of

commercially available 1000 mg/l Na standard with acidified DD water.

Working standard solutions (0.20 to 3.0 mg/l Na for low concentration and 25 to 300

mg/l Na for high concentration)


Standard blank solution: Add 1 ml KCl suppressant solution for every 20 ml acidified DD

water.

Procedure


Dilute samples with high Na so that the concentration falls within the standard calibration

curve. Pipette 20 ml of the sample to 50 ml Erlenmeyer flask and add 1 ml KCl






Calculation

Calculate mg/l Na by referring to the calibration curve.

For diluted samples, calculate original mg/l Na using:

mg/l Na = concentration x dilution factor










Analyze the blank and control sample/standard before analyzing samples. The control


for the control sample/standard should be within 5% of the known or expected

concentration.






from one of the calibration standards, while the control sample/standard is a separate






whole batch.


SODIUM (ION CHROMATOGRAPHY)

BRIUG, China

Scope

This test method covers the determination of sodium in filtered acidified sample by Ion

Chromatography (IC).



sample or enlarging the sample loop.

A small volume of sample, 100 l is introduced into an ion chromatograph. The anions of



Interference can be caused by substances such as ammonium in high concentrations

overlapping the Na peak. Sample dilution can be used to solve interference problems.

Reference

Dionex (1992), Keith (1996, EPA Method 300.7).




Pipettes, 1-25 ml





Eluent: 20 mmole/l methanesulfonic acid

Pipette 1.3 ml methanesulfonic acid into a 1 l volumetric flask, dilute to 1000 ml using

water (4.1), degas the eluent.

1000 mg/l Na+element stock solution commercial standard solution

Standard solution (0.5 to 20 mg/l Na+)

Prepare at least four standards to bracket the expected Na concentrations of the samples

Procedure








Calculation



mg/l Na+=concentrationdilution factor

The chromatogram working station can provide the content of Na+ directly.





Analyze the control standard /sample after a batch of samples. A control standard should


control sample/standard should be within 5% of the known or expected concentrations.

Analyze one set of duplicate samples. Accepted difference for duplicate samples is

10%.




whole batch.

SODIUM (ATOMIC EMISSION SPECTROSCOPY (AES)


Scope

This test method covers the determination of sodium (Na+)

in filtered acidified samples

by atomic emission spectrophotometry (AES) using an atomic absorption

spectrophotometer (AAS) instrument.


nm wavelength.

Lanthanum oxide is added as suppressant to arrest ionization interference. In AAS, KCl

is applied as suppressant.

References

American Public Health Association Water Works Association and Water Pollution

Control Federation (1985); Rodier (1975).




Pipettes, 1-25 ml

Erlenmeyer flasks, 50 ml

Reagent bottles, 500 and 250 ml, plastic

Filter, with particle retention of 0,45 m

Air compressor


La2O3 solution, 5 g/l, wet 5.8637 g La2O3 in 2% HNO3 solution, and dilute to 1000 ml

DD water.

Acetylene gas

Compressed air

1000 mg/l Na stock standard solution: Dissolve 2.542 g NaCl in 1% HNO3 solution,

dilute to 1 l with DD water

Working standard solution (0.25 to 2.0 mg/l Na): Prepare five standards to bracket the

expected concentration of the samples

Standard blank solution: Add 2.5 ml La2O3 suppressant for every 25 ml DD water

Procedure

Optimize the instrument according to the instrument’s operating manual

Dilute samples with high Na so that the concentration falls within the standard calibration

curve

Aspirate the reagent blank to zero the instrument

Aspirate each standard in turn into flame and read the emission

Aspirate the samples between standards and read the emission

Calculation

Calculate mg/l Na by referring to the calibration curve

For diluted samples, calculate original mg/l Na using

mg/l Na= concentration x dilution factor


DD water must be used in the preparation of samples/standards

Always include reagent blanks in the analysis

Add suppressant (La2O3 solution) to blanks, standards and samples


the working range. Dilute samples if necessary

Emission values should be within the acceptable working standard range, as specified in

the manufacturer’s manual

Check that the first order linearity of the standard calibration curve has r2 0.999. The

slope has to be checked in every 10 (ten) measurements together with the blank and

standard solution

Analyze the blank and calibration standard before analyzing samples

Spiking should be done after every 3 (three) samples, recovery be between 93.5 - 104.5

% is acceptable

SULFATE (INDIRECT SPECTROPHOTOMETRIC WITH BARIUM

CHROMATE AND BROMOPHENOL BLUE)


Scope

This method is applicable to untreated water samples with sulfate concentrations in the

range 20 to 100 mg/l sulfate which can be extended upwards by dilution.

The test method is based on the reaction of sulfate with barium chromate to form

insoluble barium sulfate. Liberated chromate ions are determined spectrophotometrically

at 385 nm.

Acidification eliminates interferences from bicarbonate and sulfide.

Reference

Giggenbach and Goguel (1989)


UV-Vis spectrophotometer

Water bath


Volumetric pipettes, 10 ml

Filter paper


Glacial acetic acid, AR, C2H4O2

Calcium carbonate, AR, CaCO3

Concentrated ammonium hydroxide, NH4OH

1 N HCl: Dilute 82.6 ml concentrated HCl to one liter or dilute one ampoule 1 N HCl

commercially available standard solution to one liter with DD water in a volumetric flask.

0.02 N HCl: Pipette 20 ml 1 N HCl and dilute to one liter with DD water.

2.5% (w/v) Barium chromate suspension, BaCrO4: Mix 10 ml 1 N HCl, 3 ml glacial acetic

acid and dilute to 100 ml. Add 2.5 g BaCrO4, AR. Store in polyethylene container.

45% Ammonia-Calcium solution, NH3-Ca: Dissolve 0.25 g CaCO3, AR, in a minimum

amount of 1 N HCl. Boil to expel CO2. Add 45 ml concentrated NH3 solution and dilute

to 100 ml. Prepare a fresh solution if a white gelatinous precipitate appears.

Absolute ethanol, AR, C2H6O

Bromophenol blue indicator, AR: Dissolve 0.05 g bromophenol blue powder in 20 ml

ethanol and dilute to 100 ml with DD water.

0.02 N NaOH: Pipette 20 ml 1.0N NaOH stock solution and dilute to one liter with DD

water.

Working standard solutions: Prepare at least four standards to bracket the expected


Procedure

Pipette 10 or 20 ml standard/sample to a 50 ml glass volumetric flask.

Prepare a reagent blank by similarly treating a 20 ml aliquot of DD water.

Add 2-3 drops bromophenol blue indicator. Adjust color to yellow with 0.02 N HCl.

Shake.

Adjust to first permanent faint blue color by dropwise addition of 0.02 N NaOH. Shake.

Add 2 ml BaCrO4 suspension. Shake and allow to stand for 5 minutes.

Add 0.5 ml NH3-Ca solution. Shake.

Add 5 ml ethanol and dilute to mark with DD water. Insert stopper and shake well.

Remove stopper to release pressure.

Insert stopper in flask and heat in water bath at 80oC for one hour.

Cool and shake well. Filter into a clean 50 ml glass beaker rinsed once with filtrate.


Calculation

Read sulfate concentration in mg/l directly from the instrument or prepare standard

calibration curve to obtain the sample concentration.


mg/l SO4 = concentration x dilution factor



Standard concentrations should bracket the sample concentrations and be within the

working range. Dilute samples if necessary.










concentration.






reanalyzed.





SULFATE (ION CHROMATOGRAPHY)

DOE Philippines

Scope

This method is applicable to the determination of sulfate (SO4-2

) by chemically

suppressed ion chromatography. The method detection limit for the above analyte

determined from replicate analyses is 0.30 - 50mg/l and can only be extended to 100 mg/l

by dilution. The methods works best at relatively low sulfate concentrations.

Sample is preserved by adding 1 ml of ethylenediamine to 1 l of the sample.

A small volume of sample is introduced into an ion chromatograph. The anions of

interest are separated and measured, using a system comprised of a guard column,

analytical column, suppressor device, and a conductivity detector. The chromatogram

produced is displayed in an integrator for measurement of peak height or area. The ion

chromatograph is calibrated with standard solutions containing known concentrations of

the anion(s) of interest.

Interferences can be caused by substances with retention times that are similar to and

overlap those of the ion of interest. Large amounts of an anion/cation can interfere with

the peak resolution of an adjacent analyte. Sample dilution can be used to solve most

interference problems associated with retention times.

References

Dionex Application Notes; Keith (1996, EPA note 300.0)


Ion chromatograph

Anion guard column

Anion separator column

Anion suppressor column

Conductivity detector

Gradient pump

Integrator

Balance. Analytical – capable of accurately weighing to the nearest 0.0001g

Volumetric pipettes, 1.0 to 20.0 ml

Volumetric flasks, 20.0 to 1000.0 ml

Syringe, 1 ml

Nitrogen gas, ultra high purity


1.8 mM sodium carbonate/1.7 mM sodium bicarbonate (Eluent): Dissolve 0.19078 g of

sodium carbonate (Na2CO3) and 0.14282 g of sodium bicarbonate (NaHCO3) in a 1 l

volumetric flask with reagent water and volume to mark.

Sulfate stock solution (1,000 mg/l): Dissolve 1.8141 g of potassium sulfate (K2SO4),

previously dried at 105 oC for 30 min, in reagent water and make volume 1 l. or prepare

using commercially available sulfate standard.

Working standard solutions: Prepare at least four or five standards to bracket the

expected concentration of the analyte

Reagent water: Filtered, deionized (sp. conductance 18 ohms) and degassed

Procedure

Chromatographic conditions

Column Ion Pac AS4A-4mm (polyethylvinylbenzene

divinylbenzene-aminated latex)

Eluent 1.8 mM sodium carbonate/1.7 mM sodium bicarbonate

Flow rate 2 ml/min

Injection volume 50 l

Detection Suppressed conductivity

Background reading 5-20 S

Output range 30 S

Start-up the equipment according to manual’s instructions.

Set desired integrator parameters

Chart speed:0. 5

Attenuation:1024

Peak threshold:10000


baseline is obtained.

Inject the laboratory reagent blank (LRB).

Inject calibration standards (Calibration standards are stable for one week when stored at

4oC in high-density polyethylene containers).

After calibration is established, record peak height or area, and construct calibration

curve.

Inject the LRB.

Inject the samples. Flush the sampling system thoroughly with each new sample.

Verify calibration curve after every ten samples and at the end of each day’s analysis.

Calculation

Calculate concentration of the analyte from the calibration curve

For diluted samples, calculate sulfate content,

mg/l SO4 = Concentration x Dilution Factor

Report data in mg/l. do not report data lower than lowest calibration standard.

An integration system may also be used to provide a direct readout of the concentration

of the analyte of interest.


A known amount of analyte must be added to a minimum of 10% of the routine samples.

In each case the laboratory fortified matrix (LFM) aliquot must be a duplicate of the

aliquot used for sample analysis. The analyte concentration must be high enough to be

detectable above the original sample and should not be less than four times the method

detection limit.

If the concentration of the fortification is less than 25% of the background concentration

of the matrix, the matrix recovery should not be calculated.

Calculate the percent recovery for each analyte, corrected for concentration measured in

the unfortified sample, and compare these values to the designated LFM recovery range

of 90 - 110%.

Until sufficient data becomes available (usually 20-30 analyses), assess laboratory

performance against recovery limits. When sufficient internal performance data becomes

available develop control limits from the percent mean recovery and the standard

deviation.

If the recovery of any analyte falls outside the designated LFM recovery range and the

laboratory performance for the analyte, the recovery problem encountered with the LFM

is judged to be either matrix or solution related, not system related.

In recognition of the rapid advances occurring in chromatography, the analyst is

permitted certain options, such as the use of different columns and/or eluents to improve

the separation or lower the cost of measurements.

SULFATE (TURBIDOMETRIC)

Chiang Mai University, Thailand

Scope

Sulfate is determined by its quantitative precipitation with barium chloride. Because the

finely divided barium sulfate turbidity formed is proportional to amount of sulfate in the

sample, a turbidometric reading enables the sulfate concentration to be determined

accurately.

This method is applicable to untreated water samples whose sulfate content is in the

range 1.0 – 40 mg/l.

References


Environment Federation (1992);


Magnetic stirrer

Turbidometer (Nephelometer)

Stopwatch or electric timer

Measuring spoon

Volumetric flask 100 ml

Pipettes 1, 2, 5, 10, 20 ml

Erlenmeyer flasks 250 ml.


Barium chloride (BaCl2) crystals. BaCl2 crystals should be desiccated for 24 hours then

screened to 20-30 meshes.

Buffer solution A (Required when the sample SO42-

concentration is more than 10 mg/l):

Dissolve 30.0 g magnesium chloride (MgCl2.6H2O), 5.0 g sodium acetate

(CH3COONa.3H2O), 1.0 g potassium nitrate (KNO3) and 20 ml acetic acid (CH3COOH-

99%) in 500 ml distilled water and make up to 1 l.

Buffer Solution B (Required when the sample SO42-

concentration is less than 10 mg/l):

Dissolve 30 g magnesium chloride (MgCl2.6H2O), 5 g sodium acetate

(CH3COONa.3H2O), 1.0 g potassium nitrate (KNO3), 20 ml acetic acid (CH3COOH-

99%) and, 0.111 g sodium sulphate (Na2SO4), in 500 ml distilled water and make up to 1

l.

Standard sulfate solution 100 mg/l: Dissolve 0.1479 g anhydrous Na2SO4 in distilled

water and dilute to 1.00 l.

Working standard solutions (0 to 40 mg/l): Prepare at least 4 standards to bracket the

expected concentrations of samples.

Procedure

Measure 100 ml sample or a suitable portion made up to 100 ml into a 250 ml

Erlenmeyer flask.

Add 20 ml buffer solution and mix in stirring apparatus.

While stirring, add a spoonful of BaCl2 crystals (approx. 0.352 g) and begin timing

immediately. Stir for 60+ 2 seconds.

Pour solution into absorption cell of turbid meter and measure turbidity at 5+0.5 minutes.

Preparation of calibration curve; Standards in the range 0 - 40 mg/l SO42-

Repeat steps 5.1

– 5.4 using standards instead of samples.

Calculation

Calculate mg/l SO42-

by referring to the calibration curve.

For diluted samples, calculate for final mg/l SO42-

using:

mg/l SO42-

= concentration x dilution factor


Analyze samples in duplicate. Acceptance limit is + 5%



Check that the first order linearity of the standard calibration curve has r2 > 0.999

STANDARDIZATION OF NAOH AGAINST KHP



Pipette, 5 ml



Beakers, 100 ml

Reagents

0.02 N NaOH

0.05 N potassium hydrogen phthalate, KHC8H4O4 (KHP): Weigh 5 to 10 g of primary

standard potassium hydrogen phthalate (KHC8H4O4) in a glass container and dry in an

oven at 120ºC for 2 hours. Stopper the container and cool in a desiccator. Weigh

accurately 0.95-±0.05 g of the dried KHC8H4O4, and transfer to a 500-ml container flask.

Add 100 ml of carbon dioxide-free water; stir gently to dissolve the sample.

1% phenolphthalein indicator: Dissolve 1 g of phenolphthalein in 50 ml absolute ethanol

and dilute to 100 ml with DD water.

Procedure

Pipette 5 ml of 0.05 N KHP into a 100 ml beaker.

Add 3 drops of phenolphthalein indicator and stir.

Titrate with 0.02 N NaOH until the first appearance of a permanent faint pink color.

Record the volume used.

Analyze in duplicate.

Calculation

Calculate the normality of the NaOH solution, as follows:

solution

KHPKHP

V

WN

23.204/

Where:

NKHP = Normality of KHP

WKHP = Grams KHP

Vsolution = Liters of solution

NNaOH = Normality of NaOH

VKHP = ml of KHP

VNaOH = ml of NaOH

Calculate the average normality obtained from the duplicate runs

221 NN

AVEN

STANDARDIZATION OF HCL AGAINST NAOH



Pipette, 20 ml



Beakers, 150 ml

Reagents

0.02 N NaOH (standardized against KHP)

0.02 N HCl and 0.1 N HCl

1% phenolphthalein indicator: Dissolve 1 g of phenolphthalein in 50 ml of absolute

ethanol and dilute to 100 ml with DD water.

Procedure

Pipette 20 ml of 0.02 N HCl or 5 ml of 0.1 N HCl into a beaker.

Add 3 drops of phenolphthalein indicator and stir.

Titrate with 0.02 N standardized NaOH solution until the first appearance of a permanent

faint pink color.

Record the volume used.

Analyze in duplicate.

Calculation

Calculate the normality of the HCl solution, as follows:

HCL

NAOHNAOHHCL

V

VNN

*

Where:

NHCl = Normality of HCl

NNaOH = Normality of NaOH

VHCl = Volume of HCl

VNaOH = Volume of NaOH

Calculate the average normality obtained from the duplicate runs

221 NN

AVEN

STANDARDIZATION OF SILVER NITRATE AGAINST SODIUM CHLORIDE



Pipette, 50 ml



Beakers, 150 ml

Reagents

0.10 N silver nitrate, AgNO3

0.01 N silver nitrate, AgNO3

Nitric acid, HNO3

Sodium chloride, standard solutions containing 100 mg/l Cl and 10 mg/l Cl

Procedure

Pipette 50 ml of the 100 mg/l Cl, or 100 ml of the 10 mg/l Cl standard solutions and

titrate potentiometrically or by using the Mohr method using the 0.01 N silver nitrate

solution.

Calculation

Calculate the normality of the AgNO3 solution, as follows:

3

3

*

AgNO

ClClAgNO

V

VNN

Where:

NAgNO3 = Normality of AgNO3 solution

NCl = Normality of Cl solution

VAgNO3 = ml of AgNO3 solution

VCl = ml of Cl solution

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Corporation, Norwalk, Connecticut, U.S.A.

Rodier, J. 1975. Analysis of Water. John Wiley & Sons. New York Toronto.

Shucker, G.D., T.S Magliocca and Yao-sin Su. (1975). Spectrophotometric

Determination of Boron in Siliceous Materials with Azomethine H. Anal. Chim. Acta,

75, 95-100.

Skoog and Leary. (1994). Análisis Instrumental, 4ª. Ed. McGraw-Hill/Interamericana de

España, S.A.

Vitense, K.R. and McGown, L.B. (1987). Simultaneous determination of aluminum (III)

and gallium (III) with lumogallion by phase-resolved fluorimetry. Analyst 112, 1273-

1277.

Vogel A. I. (1961). A textbook of quantitative inorganic analysis including elementary

instrumental analysis. Richard Clay and Co., Ltd., Bungay, Suffolk. Printed in Great

Britain, page 809.

APPENDIX I. ABBREVIATIONS

AAS: Atomic Absorption Spectrophotometry

AES: Atomic Emission Spectroscopy;

AR: Analytical reagent

DD: Distilled, deionized

DF: Dilution factor

HDPE: High density polyethylene

HR: High resolution

IC: Ion Chromatography

ICP: Inductively Coupled Plasma

ISE: Ion Selective Electrode

LFM: Laboratory fortified matrix

MS: Mass Spectrometry

PE: Polyethylene

QC: Quality control

SIPS: Sample Introduction Pumping System

APPENDIX II. LIST OF CONTRIBUTING LABORATORIES BY METHODS

Inorganic Non-metallic Constituents

NH3

Spectrophotometric with indophenol blue (Iceland GeoSurvey, Iceland)

Ion-selective electrode method (PNOC EDC, Philippines)

Nessler spectrophotometric method (Moi University, Kenya)

HCO3-, CO3

2-

Titrimetric method (PNOC EDC, Philippines)

B

Titrimetric (mannitol) method (PNOC EDC, Philippines)

ICP-AES method (ECGI, China)

ICP-MS method (BRIUG, China)

Spectrophotometric methods

Carmine (PNOC EDC CCLS, Philippines)

Curcumin (ICE, Costa Rica)

Azomethine-H (PNOC EDC Philippines)

AAS method (GESAL, El Salvador)

Cl-

Titrimetric methods

Mohr (PNOC EDC, Philippines)

Potentiometric (PNOC EDC, Philippines)

Spectrophotometric method (CAIR-BATAN, Indonesia)

Ion chromatography (IC) (GESAL, El Salvador)

F

Ion-selective electrode method (PNOC EDC, Philippines)

IC method (BRIUG, China)

Spectrophotometric with SPADNS (IAEA, Austria)

pH

Electrometric method (PNOC EDC, Philippines)

Total SiO2

Spectrophotometric methods

Molybdosilicate (PNOC EDC, Philippines)

Heteropoly blue (PNOC EDC, Philippines)

AAS method (GESAL, El Salvador)

ICP-AES method (DMGM, Malaysia)

SO42-

Indirect spectrophotometric (barium chromate/bromophenol blue) method (PNOC

EDC, Philippines)

IC method (DOE Philippines)

Turbidometric method (Chiang Mai University, Thailand)

Metals

Al+3

Fluorometric with lumogallion (Iceland GeoSurvey, Iceland)

Ca+2

AAS method (PNOC EDC, Philippines)

ICP-AES method (ECGI, China)

Titrimetric method (ICE, Costa Rica)

IC method (DOE, Philippines)

Fe+2

Spectrophotometric with TPTZ (Iceland GeoSurvey, Iceland)

Li+


Mg+2


IC method (BRIUG, China

K+


AES method (CAIR-BATAN, Indonesia)


ICP-AES method (IAEA Isotope Hydrology Lab)

Na+


AES method (CAIR-BATAN, Indonesia)


ICP-AES method (IAEA Isotope Hydrology Lab)

Standardization of solutions

NaOH against KHP (PNOC EDC, Philippines)

HCl against NaOH (PNOC EDC, Philippines)

AgNO3 against NaCl (PNOC EDC, Philippi

APPENDIX III. CONTACT INFORMATION OF THE CONTRIBUTIING

LABORATORIES

COUNTRY LABORATORY CONTACT

IAEA/Austria Isotope Hydrology Laboratory,

International Atomic Energy Agency

Wagramer Strasse 5

A-1400, Vienna

isotope.hydrology.laboratory

@iaea.org

China East China Institute of Technology

Fuzhou, Jiangxi, 344000

Beijing Research Institute of Uranium

Geology

Xiaoguan Dongli 10

Anwai, Beijing, 100029

Professor Mingbiao Luo

[email protected]

Mr. Dongfa Guo

[email protected]

Costa Rica Instituto Costarricense de Electricidad

P. O. Box 10032-1000 San Jose

Dr. Oscar Murillo

[email protected]

El Salvador Geotérmica Salvadoreña S. A. de C. V.

Km 11 ½ Carretera al Puerto La

Libertad desvio a Nueva San Salvador

Mr. Roberto E. Renderos

[email protected]

Iceland ISOR, Iceland Geosurvey

Grensásvegur 9

IS 108 Reykjavík

Dr. Halldor Armannsson

[email protected]

Indonesia National Resources and Environmental

Division

CAIR-BATAN

Jalan Cinere Pasar Jumat, Kotak Pos

7002

JKSKL Jakarta 12070

Dr. Zainal Abidin

[email protected]

Kenya Kenyatta University

P. O. Box 43844, Nairobi, Kenya

Professor Mwakio Tole

[email protected]

Malaysia Jabatan Mineral Dan Geosains Malaysia

Bahagian Perkhidmatan Teknikal

Jalan Sultan Azlan Shah

Peti Surat 1015

30820 Ipoh, Perak

Ms. Pauline D. Nesaraja

[email protected]

.my

Philippines Philippine National Oil Company

Energy Development Corp.

Merrit Road, Fort Bonifacio

Makati City

Department of Energy

Fort Bonifacio, Taguig, Metro Manila

[email protected]

Mr. Zalzon Espino

[email protected]

mailto:[email protected]












Thailand Geochemistry Laboratory

Department of Geological Sciences

Faculty of Science

Chiang Mai University

Professor Pongpor

Asnachinda

[email protected]


APPENDIX IV. LIST OF PERSONS INVOLVED IN DRAFTING AND REVIEW

OF THE DOCUMENT

Aragon G., Armannsson H., Arones P., Ascencio S., Cui Jianyong, Dargie M., Espino Z.,

Gabriel J., Isidor R., Lim P., Lu C., Magdadaro M., Murillo O., Nesaraja P., Nogara M.,

Olasiman R., Palabrita A., Pang Z., Pangilinan L., Panopio A., Penalosa M., Pinero E.,

Promphutha M., Solana R., Syamsu S., Tole M., Urbino G., Zapanta R.

APPENDIX V: IMPROVING ANALYTICAL QUALITY OF WATER

CHEMISTRY THROUGH INTER-LABORATORY COMPARISON

Z. Pang, M. Dargie and M. Groening

Department of Nuclear Sciences and Applications, International Atomic Energy

Agency, Vienna, Austria

Abstract. Out of a total of 40 (?) chemical laboratories that have ever participated in IAEA sponsored

inter-laboratory comparison exercises (ILCE) in the past years since 1997, we selected 21 laboratories that

have participated in three consecutive ILCEs from 1999 to 2001 and performed a statistical analysis of data

submitted by these laboratories in the ILCEs. Analytical capability of this pool of laboratories on 14

parameters including pH, electrical conductivity and minerals is assessed by the number of outliers for each

analyst, accuracy of analysis and precision of analysis. Evolution of the capability of this pool of

laboratories is evaluated by comparing the three parameters over the three years. Results show that in three

consecutive exercises in 1999, 2000 and 2001, the 21 water chemistry laboratories show continued

improvements of analytical capability. Compared to the 1999 results, in 2001, the pool of laboratories was

able to reduce the number of outliers by 3%, the coefficient of variation by 50 % (precision) and the

accuracy by 75%. This significant improvement may be attributed to enhanced skills of staff, standardized

analytical procedures and so on. The main impact of inter-laboratory comparison exercises is probably in

the recognition of errors so they can be properly corrected.

Introduction

Water chemistry data is essential in isotope hydrology investigations. In order to improve

analytical quality in laboratories in its member states, the International Atomic Energy

Agency (IAEA) has sponsored many inter-laboratory comparison exercises on

groundwater and geothermal water chemistry through its isotope hydrology programme.

Most laboratories involved in IAEA’s technical cooperation projects have participated in

this activity. Individual inter-laboratory exercises and assessment of analytical quality of

individual parameters have been reported separately [1-6]

. However, there has been a

question regarding the rationale of this activity due to the fact that analytical methods

used by different laboratories are different and the overall accepted performance is

artificially set. In this contribution, we perform a statistical analysis of analytical quality

for a selected pool of 21 laboratories (Table 1) that have participated in three consecutive

inter-laboratory comparison exercises from 1999 to 2001 to identify any possible trend in

their analytical quality with time.

About the inter-laboratory exercises

The quality of analytical data of separated water and vapour is of fundamental

importance in geochemical modelling of hydrothermal systems. To insure the analytical

quality of the geochemistry laboratories involved in such activities, Ellis (1976)

conducted the first inter-laboratory chemical analysis of geothermal waters involving

many countries. The scatter in the results during this study revealed serious deficiencies

in analytical accuracy and the need for general improvement and standardization of

analytical procedures (Giggenbach et al, 1992). Consequently, the International Atomic

Energy Agency, Vienna (IAEA) initiated inter-laboratory calibrations of geothermal

waters within the framework of the Coordinated Research Program on the Application of

Isotope and Geochemical Techniques in Geothermal Exploration in 1985. Giggenbach

(1992) reported the results of the first chemical analysis of geothermal water under this

program. The program was re-undertaken by Gerardo-Abaya et al. (1998) and presently

the program is a regular practice for comparing the analysis of geothermal waters every

year (Alvis-Isidro et al., 1999, 2000).

The objectives of this work are to analyze systematically the chemical data generated

under the IAEA Inter-laboratory calibration program and discuss a plan of action to

provide some guidance for future inter-laboratory calibrations in order to improve the

analytical quality of the participating laboratories.

Natural groundwater samples from springs and wells have been used in these inter-

laboratory exercises. In the analyses requested 14 major parameters are included: pH,

conductivity, HCO3- Cl

-, F

-, SO4

2- SiO2, NH3, Na

+, K

+, Ca

2+, Mg

2+, Li

+, and B.

Inter-laboratory Comparisons of Geothermal Water Chemistry in 1999, 2000, 2001 and

2003 have been jointly organized by the IAEA and PNOC EDC. Geothermal water

samples were collected from geothermal fields in Indonesia and Thailand in 1999 and the

Philippines in 2000, 2001 and 2003. The samples were processed by filtration using a

0.45 μm membrane filter and divided into two portions. One portion consisted of

untreated sample and the other portion was acidified with HNO3 until pH <2 was

attained. Untreated samples were analyzed for pH, conductivity, HCO3, Cl and SO4

while acidified portions were analyzed for SiO2 (total), B, F, Na, K, Ca, Mg, Li and NH3.

Geochemistry laboratories in East Asia and the Pacific, Latin American and African

regions and from other countries involved in geothermal development participated in

these activities. Results of two separate trials for each parameter were reported by the

laboratories, together with the mean, standard deviation, standard uncertainty and method

used for analyzing various parameters. Consensus values were determined from the

results of reference laboratories chosen for their expertise in geothermal water analysis.

The analytical results were evaluated using statistical tools, the AQCS (1999) and HISTO

(2000-2003) programs, involving Dixon, Grubbs, Skewness and Kurtosis tests at 95%

level of confidence. Results that passed these statistical tests were considered statistically

acceptable. However, outlying results would prompt each laboratory to review their

method and procedures to improve the accuracy of their analysis. As standard practice,

identities of the laboratories are not revealed and they are identified by laboratory codes

only.

Statistical method of analytical capability assessment

Three criteria are used in this statistical analysis: average number of statistical outliers

(NO), average weighted coefficient of variation (CV) and average weighted z-score.

They are defined and calculated as follows:

Statistical outliers (NO): values devia

- score is

calculated according to the following equation: z = (x-X)/ x = observed value, X

n.

These values are computed for each of the 14 parameters of each of the seven water samples. The

average concentrations of individual constituents of the samples from each of the three years were

used to plot the NO, CV and z-score against time.

Evolution of capability with time

Results show (Figure 1) that after participation in three consecutive exercises in 1999,

2000 and 2001, the 21 water chemistry laboratories have been able to produce analytical

results for water samples with 50% better precision and 75% better accuracy and their

results are more compatible with each other. This significant improvement may be

attributed to enhanced skills of staff, standardized analytical procedures and so on. The

main impact of inter-laboratory comparison exercises probably lies in the recognition of

errors that can be properly corrected.

Acknowledgement

We thank Pradeep Aggarwal for helpful comments on the manuscript.

Year 1999 Year 2000

Year 2001

0

5

10

15

20

25

%

Statistical outliers Coefficient of variation Z-score

Figure 1. Improved analytical quality with time for the pool of laboratories according to

three criteria: number of outliers, coefficient of variation and the z-score

Table 1. Laboratories included in this study

1 China BRIUG 8 Mexico CFE Los Azufres 15 Philippines PGI Tiwi

2 China ECGI 9 Mexico CFE Los Humeros 16 Philippines PNOC EDC CCLS

3 Colombia INGEOMINAS 10 Mexico CFE Tres Virgenes 17 Philippines PNOC EDC BGPF

4 Costa Rica ICE 11 Mexico CFE GPG Morelia 18 Philippines PNOC EDC LGPF

5 El Salvador LAGEO 12 Nicaragua ENEL 19 Philippines PNOC EDC MGPF

6 Indonesia CRDIRT-BATAN 13 Philippines DOE 20 Philippines PNOC EDC SNGPF

7 Indonesia Pertamina 14 Philippines PGI Makban 21 Thailand Chiang Mai University

Table 2. Water samples used for ILCEs included in this study

1 99-01 BRIUG 8 Mexico CFE Los Azufres 15 Philippines PGI Tiwi

2 ECGI 9 Mexico CFE Los Humeros 16 Philippines PNOC EDC CCLS

3 Colombia INGEOMINAS 10 Mexico CFE Tres Virgenes 17 Philippines PNOC EDC BGPF

4 Costa Rica ICE 11 Mexico CFE GPG Morelia 18 Philippines PNOC EDC LGPF

5 El Salvador LAGEO 12 Nicaragua ENEL 19 Philippines PNOC EDC MGPF

6 Indonesia CRDIRT-BATAN 13 Philippines DOE 20 Philippines PNOC EDC SNGPF

7 Indonesia Pertamina 14 Philippines PGI Makban 21 Thailand Chiang Mai University

References

[1] Giggenbach W. F., Goguel R. L., Humaphries W. A. (1992). IAEA inter-laboratory

comparative geothermal water analysis program. IAEA-TECDOC-641. 439-456.

[2] Pang, Z., Grőning M. and Aggarwal, P. (1997). Evaluation of an inter-laboratory

comparison exercise on groundwater chemistry for the IAEA TC project RAF/8/022,

IAEA Report. 20p.

[3] Alvis-Isidro R., Urbino G.A., Gerardo-Abaya J. (1999). 1999 interlaboratory

comparison of geothermal water chemistry under IAEA regional project RAS/8/075.

IAEA Report, 39p.

[4] Alvis-Isidro R., Urbino G.A., Pang Z. (2000). Results of the 2000 IAEA

interlaboratory comparison of geothermal water chemistry. Report, IAEA, 40p.

[5] Aggarwal, P., Dargie, M., Grőning, M., Kulkarni, K. M., and Gibson, J.J. (2001). An

Inter-Laboratory Comparison of Arsenic Analysis in Bangladesh, IAEA Report, 24p

[6] Verma, M.P., Santoyo, S., Alvis-Isidro, R., Pang, Z. (2002) Assessment of the

Results of the IAEA Interlaboratory Comparisons for Geothermal Water Chemistry.

Proceedings, 27th

Workshop on Geothermal Reservoir Engineering, Stanford

University, January 24-26, 2002.

Gerardo-Abaya J., Schueszler C., Groening M. (1998). Results of the interlaboratory

comparison for water chemistry in natural geothermal samples under RAS/8/075. Report,

IAEA, 18p.

Giggenbach W.F. (1988). Geothermal solute equilibria. Derivation Na-K-Mg-Ca

geoindicators. Geochim. Cosmochim. Acta, 37, 2749-2765.

Giggenbach W.F., Goguel R.L., Humaphries W.A. (1992). IAEA interlaboratory

comparative geothermal water analysis program. Geothermal Investigations with Isotope

and Geothermal Techniques in Latin America. IAEA-TECDOC-641. 439-456.

GGrrooeenniinngg eett aall.. 11999988 ((nneeeedd ttoo ccoommpplleettee.. oonn ssttaabbllee iissoottooppee ccaalliibbrraattiioonn,, IIAAEEAA rreeppoorrtt)).

(Zhonge please help in completing the reference).

Parr R.M., Clements S.A. (1991). Intercomparison of enriched stable isotope reference

materials for medical and biological studies. Report IAEA, 31p.

Alvis-Isidro R., Urbino G.A., Gerardo-Abaya J. (1999). 1999 interlaboratory comparison

of geothermal water chemistry under IAEA regional project RAS/8/075. Preliminary

Report, IAEA, 39p.

Alvis-Isidro R., Urbino G.A., Pang Z. (2000). Results of the 2000 IAEA interlaboratory

comparison of geothermal water chemistry. Report, IAEA, 40p.

Bevington P.R. (1969). Data reduction and error analysis for the physical sciences.

McGraw-Hill Book Company, N.Y. 336p.

Box G.E.P., Hunter W.G., Hunter J.S. (1978). Statistics for experimenters: an

introduction to design, data analysis and model building. John Wiley & Sons, N.Y. 653.

APPENDIX VI: 2003 INTER-LABORATORY COMPARISON OF

GEOTHERMAL WATER CHEMISTRY

Report by

Guima A. Urbino1 and Zhonghe Pang2*3

1PNOC Energy Development Corporation

Merritt Road, Fort Bonifacio, Makati City, 1201, Philippines

2 Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China

3 formerly at Isotope Hydrology Section, International Atomic Energy Agency, Vienna, Austria

Acknowledgement

This inter-laboratory comparison activity was made possible through the

support of the International Atomic Energy Agency through its Regional

Project RAS/8/092 on “Investigating the Environment and Water

Resources”. The authors also wish to thank all the laboratories that have

taken part in this activity either as reference or participating laboratories.

INTRODUCTION

An inter-laboratory comparison of geothermal water chemistry was jointly organized by the International Atomic Energy Agency (IAEA) and the PNOC Energy Development Corporation (PNOC EDC) in September to December 2003. This activity is part of the IAEA Regional Project RAS/8/092 on "Investigating the Environment and Water Resources". Similar inter-laboratory comparison exercises have been conducted in 1999 and 2000 under other IAEA Projects (Alvis-Isidro et al., 1999, 2001, 2002).

Thirty-one (31) laboratories participated in the 2003 inter-laboratory comparison activity from East Asia and Pacific, Latin American and African regions, besides Iceland GeoSurvey and the IAEA Hydrology laboratory. Of the 31 laboratories, five are reference laboratories, namely, Beijing Research Institute of Uranium Geology (China), Laboratorio Geoquimico LaGeo S.A. de C.V. (El Salvador), Iceland GeoSurvey (Iceland), Pakistan Institute of Nuclear Science and Technology (Pakistan) and PNOC EDC Central Chemistry Laboratory (Philippines).

The objectives of this inter-laboratory comparison are:

1. To measure the accuracy and precision of results of various chemical parameters in geothermal water analysis among participating laboratories.

2. To assess the improvement in the performance of laboratories which participated in previous inter-laboratory exercises.

3. To identify areas in which each participating laboratory may need to improve.

METHODOLOGY

Collection and Preparation of Samples

For the 2003 inter-laboratory comparison activity, only one of the three inter-laboratory comparison samples is natural geothermal water. The other two samples consist of synthetic brine and a mixture of the natural geothermal water and the synthetic brine. A water sample of medium salinity was collected from a geothermal well in the Leyte Geothermal Production Field located in the Visayas region of the Philippines, coded as GW-03-02. A standard solution with chloride concentration greater than 10,000 mg/L and calcium concentration greater than 1000 mg/L was prepared by weighing 4.585g CaCl2 (98.2%), 16.5g NaCl (99.9%), 3.58g MgCl2.6H2O (99.0%), 0.74g Na2SO4 (99.0%) and 0.95g KCl (99.5%) for every liter of solution, coded as GW-03-03. Another sample, GW-03-01, was prepared by mixing 44% GW-03-02 and 56% GW-03-03.

Each sample was filtered using a 0.45 μm membrane filter and divided into two portions. One portion consisted of an untreated sample and the other portion was acidified with HNO3 until pH <2 was attained. To ensure homogeneity, each sample was thoroughly mixed in a large plastic container before filling 1-L and 500-mL double-capped high density polyethylene sample bottles with them.

Each participating laboratory was provided with 500 mL acidified and 1 L unacidified portions of GW-03-01 and GW-03-02. Reference laboratories, except CCLS-Philippines and Iceland GeoSurvey, received 1 L acidified and 2 L unacidified portions of GW-03-01, GW-03-02 and GW-03-03. CCLS-Philippines and Iceland GeoSurvey were provided with 2 L acidified and 3 L unacidified portions of the three samples as these two reference laboratories were requested to do more analytical trials to check for homogeneity and stability of samples over time. Due to limitations in preparing large volume of synthetic brine, only the reference laboratories were provided with GW-03-03.

Analytical parameters included in this inter-laboratory comparison exercise are pH, conductivity, HCO3, Cl, SO4, SiO2 (total), B, F, Na, K, Ca, Mg, Li and NH3. Participating laboratories were requested to submit results of two separate trials of each parameter per sample together with the corresponding mean, standard deviation and standard uncertainties. Reference laboratories, on the other hand, were requested to submit results of three separate trials, except for CCLS-

Philippines and Iceland GeoSurvey, from whom results of 10 separate trials of each parameter were requested, to check for stability within a one-month period. CCLS-Philippines also conducted additional analyses to check for homogeneity of the samples. Parameters considered to be most sensitive to heterogeneity were included in homogeneity check.

Evaluation of Results

Homogeneity

A homogeneity check was carried out to ensure that there is no significant difference in the composition of the samples that would affect the evaluation of results. Ten samples of GW-03-01, seven samples of GW-03-02 and five samples of GW-03-03 were set aside for homogeneity checks. pH, Na, K, Ca, Cl and SO4 were initially chosen to check for homogeneity as these parameters were identified to be sensitive to heterogeneity.

Stability

Geothermal water samples are relatively unstable compared with

groundwater samples because of their high salinity and high silica content.

However, when properly preserved, these samples may be stable up to at

least one month. The stability checks were carried out by two laboratories,

CCLS-Philippines and Iceland GeoSurvey, to ensure that there is no

significant change in the composition of the sample within a one-month

period. Unlike the homogeneity check in which each parameter was

analyzed using separate samples, the stability check involves analysis of the

same sample at regular time intervals.

Results of all labs

Reference and participating laboratories were randomly assigned laboratory codes R1 to R5 and P1 to P26, respectively. The laboratory codes do not necessarily correspond to the order listed in Annexes A and B.

There were three levels of outlier tests conducted. The first level includes only the results of reference laboratories whose mean results were subjected to a statistical outlier test using the HISTO program (Radecki and Trinkl, 1999) to narrow down the variability of the reference values. This program includes the Dixon, Grubbs, Skewness and Kurtosis tests using a 95% level of confidence. After eliminating outliers, the remaining reference values together with the mean results of all participating laboratories, were again subjected to a second level statistical outlier test using the same program. Outliers identified in the second level outlier test were also eliminated. In the third level outlier test, values not

within +2of the initially determined mean (after two HISTO runs) were also identified as outliers.

The standard uncertainties of the analysis were significant in the evaluation of results, particularly for values that were identified as outliers. In cases in which a laboratory failed to report the standard uncertainty, standard deviation was used to estimate the uncertainty of the analysis.

As discussed above, reference values were obtained from the mean results of reference laboratories using more rigid statistical outlier tests. Three levels of statistical outlier tests were conducted on the results of reference laboratories while only two levels of outlier tests were carried out on the results of the participating laboratories. However, since n is small (4 or 5) for reference laboratories, special considerations were given in cases where two laboratories reported the same values. Otherwise, only two identical results will remain as accepted values and all other values will be considered as outliers even though the difference is within 1%, as in the case of pH and Cl in GW-03-02.

The accepted mean is the mean result of the reference and participating laboratories for each parameter excluding outliers identified up to the second level statistical outlier test while the final accepted mean is the mean result of

reference and participating laboratories excluding outliers identified up the third

level outlier test (two HISTO runs and values not within + 2

For the synthetic samples, GW-03-01 and GW-03-03, expected values for some parameters were calculated based on the preparation of these samples mentioned earlier. For GW-03-03, losses in Ca and Cl were calculated taking into account the possible precipitation of Ca as CaCl2.

DISCUSSSION OF RESULTS

The data for the homogeneity check is presented in Table 1. For GW-03-01, the coefficient of variation (CV) ranges from 0.36% to 1.74% with K having the highest CV. For GW-03-02, the CV ranges from 0.12% to 1.98 with K also having the highest CV. For GW-03-03, the CV ranges from 0.41% to 1.36% with Na having the highest CV. These values indicate that K tends to have the highest variability. However, the low range of CV values indicates no significant difference in the composition of the samples. Thus, GW-03-01, GW-03-02 and GW-03-03 are considered homogeneous.

Tables 2A and 2B shows results of stability checks performed by CCLS-Philippines and Iceland GeoSurvey, coded as Laboratory 1 and Laboratory 2 (not necessarily in that order). Results indicate no significant trends in increase or decrease of values with time of the various parameters analyzed except pH and HCO3 wherein a slight increase in pH and slight decrease in HCO3 are detected in the natural geothermal brine, GW-03-02. However, the effect is not quite significant as indicated by the CV that ranges from 0.9% to 3.6%. Other parameters with CV greater than 5% may be due to poor precision of the analysis.

The mean results of reference and participating laboratories are presented in Table 3 for GW-03-01 (mixed natural and synthetic brine), Table 5 for GW-03-02 (natural geothermal brine) and Table 7 for GW-03-03 (synthetic brine). Outliers identified using the HISTO program in the first level statistical test for reference laboratories are marked with a red asterisk (*). For the second level statistical

test, outliers are marked with a black asterisk (*) and values not within +2 are marked with a plus sign (+).

The S-shaped plots in Figures 1 to 37 show the results of all laboratories for the various parameters of each sample. The mean result of each laboratory and identified outliers are represented by open red diamonds (♦) and black-filled diamonds (♦), respectively. The standard uncertainties are also depicted in the graphs as error bars. The reference value, which is the mean of all accepted results of the reference laboratories excluding outliers, is represented by a blue

solid line with its +2as blue broken lines. The accepted mean is represented

by a black solid line with its +2as black broken lines. A red solid line represents the final accepted mean. For GW-03-01 and GW-03-03, the expected values are shown by a green solid line.

For all outlying results, standard uncertainties were considered in the evaluation.

When an outlying value with its uncertainty within +2value becomes acceptable. However, it has been noted that some laboratories have reported large standard uncertainty values that may not represent the actual uncertainties of the analysis. In this evaluation, the values are presented as reported by the laboratories.

The analytical methods used by the different laboratories for GW-03-01, GW-03-02 and GW-03-03 are shown in Tables 4, 6 and 8, respectively.

GW-03-01 Mixed Natural and Synthetic Brine

In GW-03-01, the final accepted mean of all parameters is within +2reference value except for Ca. The final accepted mean for Ca is 788 mg/L while

+2

Ca is 776 mg/L which is within +2

Reference values generally lie close to the expected values except for SO4, Na and K wherein the final accepted mean is closer to the expected value.

The percentage of accepted results for all parameters ranges from 71.4% to 96.4% with Ca having the lowest % accepted results.

GW-03-02 Natural Brine

In GW-03-02, the final accepted means of all parameters are within +2reference value except for B wherein the final accepted mean is 25.0 mg/L

outside +2variation is not quite significant as the difference from the reference value (25.7 mg/L) is only 2.7%.

The percentage of accepted results for all parameters ranges from 75.0 to 93.5% with NH3 having the lowest % accepted results.

GW-03-03 Synthetic Brine

Only reference laboratories analyzed the synthetic brine GW-03-03. As the composition of this sample is known, the mean of all results for Cl, SO4, Na, K, Ca and Mg were compared with the expected values of these parameters. All

expected values are within +2

expected value is 1626 mg/L outside +2mg/L. Low recovery in Ca indicates that precipitation of CaCl2 occurred. Hence, the expected values of Ca and Cl were recalculated to account for losses in Ca. With recalculated values for Ca and Cl, the recoveries for SO4, Na, K and Cl range from 96.5 to 98.9%, with recovery for Ca excluded as this was reset at 100%.

The percentage of accepted results for all parameters ranges from 60 to 100% with Mg having the lowest % accepted results.

Laboratory Performance in Inter-laboratory Comparison

For GW-03-01, 48.4% of all the reference and participating laboratories obtained % accepted results >90% including three out of five reference laboratories (Fig. 39). These laboratories are R2, R3, R4, P2, P5, P6, P7, P10, P11, P14, P15, P18, P20, 21 and P23. For GW-03-02, 45.2% obtained % accepted results >90% including four out of five reference laboratories (Fig. 40). These laboratories are R1, R2, R3, R4, P2, P3, P5, P6, P7, P11, P17, P18, P21 and P23. For GW-03-03, reference laboratories R2, R3, R4 and R5 obtained % accepted results >90%.

For GW-03-01 and GW-03-02, five out of the thirty-one laboratories or 16.1% obtained accepted results <70%. It may be noted that four out of these five laboratories consistently obtained low percent recoveries, namely, R5, P1, P4 and P19.

Parameters for which the lowest accepted results were obtained are Ca for GW-03-01, NH3 for GW-03-02 and Mg for GW-03-03.

Twenty-eight of the thirty-one laboratories that participated in this activity, have also participated in previous inter-laboratory comparison exercises organized by the IAEA in 1999, 2000 and 2001 (Alvis-Isidro et al, 1999, 2001, 2002). Of these twenty-eight laboratories 82%have either improved their performance or maintained >80% accepted results. Of the seventeen laboratories that participated in all four inter-laboratory comparison activities, 82% have either improved their performance or maintained at least 80% accepted result.

CONCLUSIONS AND RECOMMENDATIONS

The inter-laboratory comparison of geothermal water chemistry results is a useful tool for each laboratory to monitor and improve its performance by comparing their results with other laboratories. Several laboratories that have participated in this activity over the years have either improved or maintained their good performance in the analysis of geothermal water samples. (See Alvis-Isidro et al, 1999, 2001, 2002, respectively, for results of the previous exercises). Laboratories, whose results have been identified as statistical outliers, are guided in the effort to identify which parameters call for improvement. Laboratories whose results are not identified as outliers but significantly deviate from the final accepted mean or reference value should also be cautioned to reconsider their analytical procedures.

Based on the results of this inter-laboratory comparison exercise, it has been observed that some laboratories may need to establish their standard uncertainties for the different parameters since this is also a part of the quality control measures each laboratory has to undertake. Knowing these values also increases confidence of the laboratory in the validity of their analysis.

As a continuing activity, it is also recommended that the conduct of this inter-laboratory comparison be further improved by adopting measures recommended by ISO/IEC Guide 43 (IOS,1997) and other references on proficiency testing applicable to geothermal water chemistry.

REFERENCES

Alvis-Isidro, R., Urbino, G.A. and Gerardo-Abaya, J. (1999) 1999 Inter-laboratory comparison of

geothermal water chemistry. IAEA report.

Alvis-Isidro, R., Urbino, G.A. and Pang, Z. (2001) Results of the 2000 IAEA inter-laboratory

comparison of geothermal water chemistry. IAEA report.

Alvis-Isidro, R., Urbino, G.A. and Pang, Z. (2002) Results of the 2001 IAEA inter-laboratory

comparison of geothermal water chemistry. IAEA report.

International Organization for Standardization (IOS). (1997) ISO/IEC 43-II. Proficiency Testing

by Inter-laboratory Comparisons, Switzerland.

Radecki, Z. and Trinkl, A. (1999) HISTO-Statistical analysis for inter-comparison data. IAEA

report.

LIST OF TABLES, FIGURES AND ANNEXES

Tables

Table 1

Homogeneity Check

Table 2A

Stability Check – CCLS Philippines

Table 2B

Stability Check – GeoSurvey Iceland

Table 3

Mean Results of All Laboratories for GW-03-01

Table 4 Analytical Methods Used for GW-03-01

Table 5



Table 7



Figures

Fig. 1

S-shaped plot of pH results for GW-03-01

Fig. 2 S-shaped plot of Conductivity results for GW-03-01

Fig. 3 S-shaped plot of HCO3 results for GW-03-01

Fig. 4 S-shaped plot of Cl results for GW-03-01

Fig. 5 S-shaped plot of SO4 results for GW-03-01

Fig. 6 S-shaped plot of SiO2 results for GW-03-01

Fig. 7 S-shaped plot of B results for GW-03-01

Fig. 8 S-shaped plot of F results for GW-03-01

Fig. 9 S-shaped plot of Na results for GW-03-01

Fig. 10 S-shaped plot of K results for GW-03-01

Fig. 11 S-shaped plot of Ca results for GW-03-01

Fig. 12 S-shaped plot of Mg results for GW-03-01

Fig. 13 S-shaped plot of Li results for GW-03-01

Fig. 14 S-shaped plot of NH3 results for GW-03-01

Fig. 15















Fig. 29










Fig. 38 % Accepted Results per Parameter

Fig. 39 % Accepted Results of Laboratories in the Analysis of

Mixed Geothermal and Synthetic Brine (GW-03-01)


Geothermal Brine (GW-03-02)


Synthetic Brine (GW-03-03)

Fig. 42 % Overall Accepted Results

Fig. 43 Comparison of % Overall Accepted Results (1999-2003)


Laboratory Code

pH Cond. HCO3 Cl SO4 SiO2 (total)

B F Na K Ca Mg Li NH3

R1 pH CM TM CO TU - - - AA AA AA AA - -

R2 pH - TM TM CO CO TM ISE AA AA AA AA AA ISE

R3 pH CM TM TM CO AA CO - AA AA AA AA AA -

R4 pH CM TM IC IC CO CO IC AA AA AA AA AA CO

R5 pH CM TM IC IC ICP-MS ICP-MS IC IC IC IC IC ICP-MS CO

P1 pH CM TM TM CO CO - - - - - - - -

P2 pH CM TM TM TU AA CO - AA AA AA AA - -

P3 pH CM TM TM TU ICP-AE TM ISE AA AA ICP-AE ICP-AE - -

P4 pH CM TM IC IC CO CO IC IC IC IC IC IC IC

P5 pH CM TM TM CO AA TM ISE AA AA TM AA AA ISE

P6 pH CM TM TM CO CO TM ISE AA AA AA AA AA -

P7 pH - - TM TU AA CO - AA AA AA AA - -

P8 pH CM TM TM TU CO - ISE AA AA AA AA FE

P9 pH CM TM TM CO CO TM - - - - - - -

P10

P11 pH CM TM IC IC ICP-AE ICP-AE IC AA AA ICP-AE ICP-AE AA CO

P12 pH CM TM TM CO AA TM ISE AA AA AA AA AA ISE

P13 pH CM TM TM CO CO TM IC AA AA AA AA AA CO

P14 pH CM TM TM TU CO CO ISE AA AA AA AA AA ISE

P15 pH CM TM TM TU AA CO ISE AA AA AA AA AA ISE

P16 pH CM TM TM TU - - ISE AA AA TM TM AA -

P17 pH CM TM TM CO ICP-AE ICP-AE ISE AA AA ICP-AE ICP-AE AA -

P18 pH CM TM TM CO AA TM - AA AA AA AA AA -

P19 pH CM TM CO CO CO CO CO FE FE AA AA FE CO

P20 pH - TM TM CO CO TM - AA AA AA AA AA ISE


P22 pH CM TM TM CO CO TM ISE AA AA AA AA AA ISE

P23 pH - TM TM CO CO TM - AA AA AA AA - ISE

P24 pH CM TM TM TU AA - - AA AA AA AA AA -


P26 pH CM TM IC IC - - - - - - - - ISE

Code Method Code Method

AA Atomic Absorption TU Turbidimetry

FE Flame Emission GM Gravimetry

IC Ion Chromatography TM Titrimetry

ICP-MS Inductively couple plasma with mass spectrometry pH pH measurement

ICP-AE Inductively couple plasma with atomic emission CM Conductivity

HPLC High performance liquid chromatography ISE Ion selective electrode

CO Colorimetry


Laboratory Code

pH Cond. HCO3 Cl SO4 SiO2 (total)



R2 pH - TM TM CO CO TM ISE AA AA AA AA AA ISE

R3 pH CM TM TM CO AA CO - AA AA AA AA AA -


R5 pH CM TM IC IC ICP-MS ICP-MS IC IC IC IC IC-MS ICP-MS CO

P1 pH CM TM TM CO CO - - - - - - - -

P2 pH CM TM TM TU AA CO - AA AA AA AA - -

P3 pH CM TM TM TU ICP-AE TM ISE AA AA ICP-AE ICP-AE - -

P4 pH CM TM IC IC CO CO IC IC IC IC IC IC IC

P5 pH CM TM TM CO AA TM ISE AA AA TM AA AA ISE

P6 pH CM TM TM CO CO TM ISE AA AA AA AA AA -

P7 pH - - TM TU AA CO - AA AA AA AA - -

P8 pH CM TM TM TU CO - ISE AA AA AA AA FE

P9 pH CM TM TM CO CO TM - - - - - - -

P10

P11 pH CM TM IC IC ICP-AE ICP-AE IC AA AA ICP-AE ICP-AE AA CO

P12 pH CM TM TM CO AA TM ISE AA AA AA AA AA ISE

P13 pH CM TM TM CO CO TM IC AA AA AA AA AA CO

P14 pH CM TM TM TU CO CO ISE AA AA AA AA AA ISE

P15 pH CM TM TM TU AA CO ISE AA AA AA AA AA ISE

P16 pH CM TM TM TU - - ISE AA AA TM TM AA -

P17 pH CM TM TM CO ICP-AE ICP-AE ISE AA AA ICP-AE AA AA -


P19 pH CM TM CO CO CO CO CO FE FE AA AA FE CO


P21 pH - TM TM CO CO CO - AA AA AA AA AA ISE

P22 pH CM TM TM CO CO TM ISE AA AA AA AA AA ISE

P23 pH - TM TM CO CO TM - AA AA AA AA - ISE

P24 pH CM TM TM TU AA - - AA AA AA AA AA -


P26 pH CM TM IC IC - - - - - - - - ISE








CO Colorimetry


Lab Code pH Cond. HCO3 Cl SO4 SiO2 (total)



R2 pH - TM TM CO CO CO ISE AA AA AA AA AA ISE

R3 pH CM TM TM CO - CO - AA AA AA AA AA -


R5 pH CM TM IC IC ICP-MS ICP-MS IC IC IC IC IC ICP-MS CO








CO Colorimetry

P9

P14 R

5

P2

P4

R4

P11

P22

P24

P26 P8

P19 R

1

R3

P1

P10 P6

P5

P25

P13

P15 P3

P17

P18

P16

P12

Lab Code

15000

20000

25000

30000

35000

Con

duct

ivity

, µS

/cm

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P17

P13

P10

P22

P25 P6

P23 P3

P14

P20 R

1P

12P

24 R3

P4

P15

P11

P26 P2

P21

P19 P5

P7

P8

R2

P9

P18

P16 R

4R

5P

1

Lab Code

6.4

6.8

7.2

7.6

8

8.4pH

, Uni

ts

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean

Fig. 1 S-shaped plot of pH results for GW-03-01

P8

R5

P3

P20

P12

P18 P9

P1

P24

P14 R

2

P19 P6

P21

P13

P17

P23

P26 R

3

P5

R4

P22 P2

P16

P11 R

1

P15

P25 P4

Lab Code

0

50

100

150

200

250

HC

O3,

mg/

L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P2

6P

25

P8

P1

4P

3P

7R

5P

15

R2

P1

2P

21

P1

7P

1P

18

P5

P1

6P

20

R3

R4

P6

P2

P1

0P

9P

23

P1

3P

22

R1

P1

9P

11

P2

4P

4

Lab Code

8000

9000

10000

11000

12000

Cl,

mg

/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P12 R

2P

7P

10 R5

P4

P23 R

1P

26P

21 P9

P6

R3

R4

P1

P15 P2

P20

P11 P8

P5

P3

P17

P13

P16

P25

P14

P18

P24

P22

P19

Lab Code

250

300

350

400

450

500

SO

4, m

g/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P1

P2

2

R2

P9

P4

P8

P6

P1

4

P1

1

P1

3

P2

3

R5

P1

7

R4

P7

P2

1

P2

P1

5

P2

0

P5

P1

2

R3

P1

8

P2

4

P3

P2

5

P1

9

Lab Code

0

200

400

600

SiO

2, m

g/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P3

P6

P2

2

P2

1

P1

8

P2

5

P7

P9

P1

3

P2

3

P4

P5

R2

R4

R5

R3

P1

0

P1

1

P1

4

P1

2

P2

0

P1

5

P2

P1

7

P1

9

Lab Code

0

4

8

12

16

20

24

B, m

g/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P6

P1

6

P1

2

P3

R5

P8

R4

P1

7

P2

2

P1

4

P5

P1

5

R2

P1

1

P1

0

P4

P1

9

P1

3

Lab Code

-4

0

4

8

12

F, m

g/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


R5

P1

4

P2

5

P3

P2

0

R1

P1

3

P1

2

P1

0

P2

3

R4

P2

1

R3

P1

8

P1

1

P5

P1

7

P7

P1

6

P2

R2

P2

4

P2

2

P1

9

P8

P1

5

P6

P4

Lab Code

3000

4000

5000

6000

Na

, mg

/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P2

1

P2

3

P1

2

P2

0

P7

R5

P2

5

R2

P3

P2

R3

R1

P1

3

P1

6

P8

P1

7

R4

P1

4

P1

1

P1

8

P2

4

P5

P6

P1

5

P2

2

P4

P1

0

P1

9

Lab Code

200

400

600

800

1000

K, m

g/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


R5

P2

2

P5

P1

2

P2

4

P1

6

R4

R3

P1

1

R2

P1

4

P2

P1

7

P1

3

P2

1

P7

P8

P2

0

P6

P1

5

P2

3

P1

0

R1

P3

P1

8

P4

P2

5

P1

9

Lab Code

600

800

1000

1200

Ca

, m

g/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P1

6

R5

P1

4

R4

P1

0

P1

7

P6

R1

R2

P2

1

P1

2

P2

P5

P1

1

P7

P1

5

P2

3

R3

P2

0

P2

2

P2

4

P1

8

P2

5

P3

P1

3

P4

P8

P1

9

Lab Code

160

200

240

280

320

360

Mg

, mg

/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P2

1

P2

4

P1

9

R2

P1

6

P1

2

P1

5

P5

P2

0

P2

2

R4

P1

7

R5

P2

5

P1

4

P1

8

P8

R3

P6

P1

1

P4

P1

0

P1

3

Lab Code

-8

-4

0

4

8

Li,

mg

/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P4

P1

3

P1

9

P2

6

P1

4

R5

P2

3

R4

P1

2

P5

P1

1

R2

P1

5

P2

0

P2

2

Lab Code

0

4

8

12

NH

3, m

g/L

GW-03-01

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Expected Value

Final Accepted Mean


P19

P13

P25

P21

P15

P22

P24

P12

P23 P9

P20 P5

P26 P3

R1

P4

P7

P11

P17 P6

P8

R3

P2

P18

P14 R

4R

2P

1P

10P

16 R5

Lab Code

6.4

6.8

7.2

7.6

8pH

, Uni

ts

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean

Fig.15 S-shaped plot of pH results for GW-03-02

P9

P1

4

P2

2

P2

4

R5

P1

7

P1

1

R4

P1

6

P2

P4

P1

P2

5

P1

8

P6

R3

P2

6

R1

P1

0

P1

3

P5

P8

P3

P1

5

P1

9

P1

2

Lab Code

2000

4000

6000

8000

Co

nd

uct

ivity

, µS

/cm

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P8

R5

P3

P2

2

P2

4

P1

8

P2

0

P2

6

P9

P1

7

R2

P6

P1

P1

2

P1

3

P2

1

P2

3

R3

P5

R4

P1

6

P2

P1

1

P1

9

R1

P1

4

P1

5

P2

5

P4

Lab Code

0

100

200

300

400

500

HC

O3, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P2

6R

5P

22

P2

5P

16

P7

P1

8P

17

P1

4P

20

P1

1P

9R

2P

3R

1R

4P

21

R3

P1

2P

5P

23

P1

3P

15

P2

P8

P1

P6

P2

4P

10

P4

P1

9

Lab Code

1200

1400

1600

1800

Cl,

mg

/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P26

P18 P7

R4

P5

R5

P4

P11 P3

P2

P9

P6

R3

P15

P25

P21

P20

P12

P10

P13

P23 P8

P17 R

2P

24 P1

R1

P16

P19

P22

P14

Lab Code

500

600

700

800

900

SO

4, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P1

P1

9

P9

P1

7

P4

P1

3

P2

R4

P7

P2

1

P5

P2

3

R3

R2

P1

1

P2

2

P2

0

P1

5

P1

4

P1

8

R5

P6

P3

P1

2

P2

4

P2

5

P8

Lab Code

0

400

800

1200

SiO

2, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P6

P22

P14

P18 P3

P25 P9

P13 P4

P21

P23 P5

R3

R4

R2

P15

P11

P20 P7

P10

P12 P2

R5

P17

P19

Lab Code

10

20

30

40

50

B, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P1

3

P1

4

R5

P6

P8

P1

2

R4

P1

6

P1

7

P1

1

P3

R2

P1

5

P5

P4

P2

2

P1

0

P1

9

Lab Code

-4

-2

0

2

4

6

8

F, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P1

4

P2

0

P3

P5

P1

6

P2

4

R5

P1

2

P2

3

R4

P1

7

P2

1

P7

P1

8

P1

0

P2

R3

P1

3

R2

P1

1

R1

P6

P2

5

P1

5

P8

P2

2

P4

P1

9

Lab Code

800

1000

1200

1400

1600

Na

, mg

/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P1

1

P2

5

P2

1

P2

3

P1

4

R3

P8

P2

P7

R2

P1

6

P1

7

P1

2

P2

0

P1

3

R4

R1

P2

2

P5

P6

P1

5

P1

8

R5

P3

P2

4

P4

P1

0

P1

9

Lab Code

100

150

200

250

300

350

K, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P2

1

P2

5

P2

4

P1

6

P2

3

P2

0

R4

P7

P6

P5

P1

1

R2

P1

2

R3

P1

9

P2

P1

0

P1

4

P1

8

P1

7

R5

P2

2

P1

3

P4

P8

P3

P1

5

Lab Code

0

5

10

15

20

25

30C

a, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P4

P1

3

P2

4

P2

5

R3

P5

P2

2

R2

P7

R4

P2

1

P1

1

P2

R5

P1

8

P2

0

P6

P2

3

P8

P1

9

P1

4

P3

P1

7

P1

0

P1

5

P1

2

P1

6

Lab Code

0

0.4

0.8

Mg

, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P1

3

P1

9

P2

0

P1

4

P5

P1

1

R5

P2

1

R4

R2

P2

6

P1

2

P2

3

P1

5

P2

2

P4

Lab Code

0

5

10

15

20

25

NH

3, m

g/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


P2

1

P1

5

R5

P1

2

P2

4

P5

P1

7

P1

3

P1

9

P6

R4

R2

P2

5

P8

P1

8

P1

6

P1

1

R3

P2

2

P4

P2

0

P1

4

P1

0

Lab Code

-20

-10

0

10

20

Li,

mg

/L

GW-03-02

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Reference Value

Reference Value±2

Final Accepted Mean


R5

R4

R1

R3

Lab Code

20000

30000

40000

50000

Co

nd

uctivity, µ

S/c

m

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2


R3

R5

R1

R2

R4

Lab Code

5.6

6

6.4

6.8p

H, U

nits

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Fig. 29 S-shaped plot of pH results for GW-03-03

R5

R2

R3

R1

R4

Lab Code

12000

13000

14000

15000

16000C

l, m

g/L

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Expected Value

Recalculated Expected Value


R2

R1

R5

R4

R3

Lab Code

20

40

60

80

SO

4, m

g/L

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Expected Value


R1

R5

R4

R2

R3

Lab Code

5000

6000

7000

8000

Na

, m

g/L

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Expected Value


R2

R3

R4

R5

R1

Lab Code

400

500

600

K, m

g/L

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Expected Value


R4

R5

R3

R2

R1

Lab Code

1200

1300

1400

1500

1600

1700C

a, m

g/L

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Expected Value

Recalculated Expected Value


R4

R1

R2

R5

R3

Lab Code

400

420

440

Mg

, m

g/L

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2

Expected Value


R2

R4

R5

Lab Code

0.1

0.2

0.3

0.4

NH

3, m

g/L

GW-03-03

Accepted Results

Outliers

Accepted Mean

Accepted Mean ±2


pH

Con

d

HC

O3 Cl

SO

4

SiO

2 (t

otal

) B F

Na K

Ca

Mg Li

NH

3

Parameter

0

20

40

60

80

100

% A

ccep

tab

le R

esu

lts

GW-03-01

GW-03-02

GW-03-03

Fig. 38 % Accepted Results per Parameter

R4

P5

P1

1

R2

P6

R3

P2

0

P2

P7

P1

4

P1

5

P1

8

P1

0

P2

1

P2

3

P1

2

P9

P1

7

P8

P2

5

P2

6

P1

6

P2

4

R1

P3

R5

P1

3

P2

2

P1

P4

P1

9

Laboratory Code

0

20

40

60

80

100

% A

cce

pte

d R

esu

lts

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

No

. of

Su

bm

itte

d R

es

ult

s

Fig. 39 % Accepted Results of Laboratories in the Analysis of Mixed Geothermal and Synthetic Brine (GW-03-01)

P5

P11 R

2

P17

P18 P2

P23 P7

R1

R4

P6

R3

P3

P21

P12

P14

P15

P22 P9

P20

P25

P26

P16

P24

P13 P8

P10 P1

R5

P4

P19

Laboratory Code

0

20

40

60

80

100

% A

ccep

ted

Res

ult

s

0

1

2

3

4

5

6

7

8

9

10

11

12

13

14

No

. of S

ub

mitt

ed R

esu

lts

Fig. 40 % Accepted Results of Laboratories in the Analysis of Geothermal Brine (GW-03-02)

R2

R5

R4

R3

R1

Laboratory Code

0

20

40

60

80

100

% A

cce

pte

d R

esu

lts

0

4

8

12

16

No

. of

Su

bm

itte

d R

es

ult

s

Fig. 41 % Accepted Results of Laboratories in the Analysis of Synthetic Brine (GW-03-03)

R2

P5

P1

1

P2

P7

P6

P2

3

R4

R3

P1

7

P1

8

P2

0

P2

1

P1

4

P1

5

R1

P1

2

P9

P3

P2

5

P2

6

P1

6

P2

4

P1

0

P8

R5

P1

3

P2

2

P1

P4

P1

9

Laboratory Code

0

20

40

60

80

100%

Ac

ce

pte

d R

esu

lts

01234567891011121314151617181920212223242526272829303132333435363738394041

No

. of

Su

bm

itte

d R

es

ult

s

Fig. 42 % Overall Accepted Results (2003)

R1

R2

R3

R4

R5

P1

P2

P3

P4

P5

P6

P7

P8

P9

P1

0P

11

P1

2

P1

3

P1

4

P1

5

P1

6

P1

7

P1

8

P1

9

P2

0

P2

1

P2

2

P2

3

P2

4

P2

5

P2

6

Laboratory Code

0

20

40

60

80

100%

Ac

ce

pte

d R

esu

lts

1999

2000

2001

2003

Fig. 43 Comparison of % Overall Accepted Results (1999-2003)

ANNEX A

2003 IAEA INTER-LABORATORY COMPARISON

OF GEOTHERMAL WATER CHEMISTRY

LIST OF PARTICIPATING LABORATORIES

1. COUNTRY 2. NAME/ADDRESS OF LABORATORY NAME/FAX NO./E-MAIL ADDRESS

OF CONTACT PERSON

IAEA Isotope Hydrology Laboratory

International Atomic Energy Agency

Wagramerstrasse 5

Vienna, Austria

Ms. Marina Dargie

Fax: 43-1-26007

E-mail: [email protected]


China East China Institute of Technology, 14

Huangchengxilu, Fuzhou,

Jiangxi 344000

Mr. Luo Mingbiao

Tel.: 86 794 8258300

Fax: 86 794 8258618


Colombia

INGEOMINAS

Laboratorio de Aguas y Gases

Diagonal 53 No. 34-53

Bogota, Colombia

Mr. Luis Enrique Lesmes M.

Tel.: 57-1-2200255

Fax: 57-1-2223515


Costa Rica Laboratorio Geoquimico, Plantel Guayabo de Bagaces

Instituto Costarricense de Electricidad

UEN Proyectos y Servicios Asociados

Centro de Servicio Recursos Geotermicos

Apartado 10032-1000

San Jose, Costa Rica , America Central

Ms. Biyun Zhen Wu

Tel.: 506) 6730100

Fax: (506) 6730132




3. COUNTRY NAME/ADDRESS OF LABORATORY NAME/FAX NO./E-MAIL ADDRESS OF CONTACT PERSON

Guatemala Unidad de Estudios y Desarrollo

Geotermicos

Empresa de Generacion de Energia Electrica, INDE

7a. Avenida 2-29 Zona 9

Guatemala, C. A. 01-009

Mr. Alfredo Rene Roldan Manzo

Fax: 502-3345036

E-mail: [email protected] or [email protected]

Indonesia Hydrology and Geothermic lab

Natural Resources and Environmental Div.

CDRIRT-BATAN

P3TIR - Batan

Jl Cinere Ps Jumat, Jakarta 12070

Indonesia

Mr. Zainal Abidin

Tel: 062 21 7659376

Fax: 062 21 7691607

E-mail:[email protected]

Kenya Olkaria Geothermal Project

P.O. Box 785,

Naivasha,

KENYA

Mr. Zacchaeus Wambua Muna

Chief Geothermal Scientist

P.O. BOx 1143,

NAIVASHA,



KENYA

Tel.: 254-050-20070,

Mob.: 0733-734-153


Korea Analytical Chemistry Laboratory

Korea Atomic Energy Research Institute Nuclear Chemistry Research Team

Yusong, Taejon, Korea, 305-600

Mr. Jong-Goo KIM

P.O. Box 105, Yusong, Taejon, Korea, 305-600

Tel.: +82-42 868 2483

Fax: +82-42 868 8148

E-mail address: [email protected]

4. COUNTRY 5. NAME/ADDRESS OF LABORATORY NAME/FAX NO./E-MAIL ADDRESS OF CONTACT PERSON

Malaysia Department of Geoscience and Mineral Malaysia (GSM)

Division of Technical Services

Jalan Sultan Azlan Shah

30820 Ipoh, Perak, Malaysia

Ms. Pauline Dushyanthi Nesaraja

Tel.: 605-5457644

Fax: 605-5468479





Department of Geoscience and Mineral Malaysia (Sabah)

Jalan Penampang

Beg berkunci 2042

88999 Kota Kinabalu

Sabah, Malaysia

Mr. Khairun Nasir Moktar

Tel.: 088-260311

Fax: 088-240150


Mexico CFE Gerencia de Proyectos

Geotermoelectricos

Alejandro Volta 655

Col. Electricistas CP 58290

Morelia, Michoacan, Mexico

CFE. Residencia Los Azufres

Alejandro Volta # 655

Col. Electricistas CP 58290

Morelia, Michoacán, México

Mr. Enrique Tello Hinojosa

Tel.: 52-42-227107

Fax: 52-43-3227060


Mr. Fernando Sandoval Medina

Tel.: 52-443-3-15-32-46

Fax : 52-443-3-15-35-41


or [email protected]




México

(cont.)

CFE Residencia Las Tres Virgenes CFE a un costado del Parque de material

Col. La Villita C.P. 23920

Santa Rosalia, B.C.S., México

CFE Residencia Los Humeros

Carretera Perote-Humeros km 20

Maxtaloya, Puebla, Mexico

Geothermal Department of Instituto de Investigaciones Electricas

Gerencia de Geotermia

Av. Reforma 113, Palmira

62490 Cuernavaca, Morelos, Mexico

Ms. Ruth Tapia Salazar

Tel.: 52-115-22266

Fax: 52-115-22366


Mr. Rigoberto Tovar Aguado

Tel.: 52-282-52273

Fax: 52-282-52274


Mr. Eduardo Iglesias

Tel.: 00 52 777 318 3811 ext. 7305

Fax: 00 52 777 318 2526

E-mail: [email protected].



Nicaragua Laboratorio de Geoquimica

Gerencia de Geotermia, ENEL

Del Colegio Cristo Rey 4 cuadras al sur

Barrio Largaespada

Managua, Nicaragua

Ms. Melba Su Hurtado

Tel.: 505-2401176/ 2401276/ 2787824

Fax: 505-2401276


Panama Directora Nacional de Investigación Sientifica

Secretaria Nacional de Ciencia, Tecnologia e Innovación

Edificio 213, Ciudad del Saber, Clayton, Panama

Ms. Denis Vega

Tel.: +507-317-0014

Fax: +507- 317-0014



Philippines

(cont.)

PNOC EDC BacMan Geothermal

Production Field

Sorsogon, Sorsogon, Philippines

Mr. Ramonito Solis

Tel.: 63-2-7597186

Fax: 63-2-7597185




PNOC EDC Leyte Geothermal

Production Field

Tongonan, Leyte, Philippines

PNOC EDC Mindanao Geothermal

Production Field

Kidapawan, North Cotabato, Philippines

PNOC EDC Southern Negros Geothermal

Production Field

Ticala, Valencia, Negros Oriental, Philippines

Mr. Ramon Solaña

Tel.: 63-2-7597192 or 7597193

Fax: 63-2-7597189


Mr. James B. Nogara

Tel.: 63-2-7597194

Fax: 63-2-7597195


Mr. Orlando Maturgo

Tel.: 63 2 7597187

Fax: 63 2 7597188





Department of Energy

Fort Bonifacio, Taguig, Metro Manila Philippines

Ms.Tess Ocampo

Tel.: 63-2-8401401

Fax: 63 2 8402093

E-mail:


Philippines

(cont.)

Mak-Ban Chemistry Laboratory

Philippine Geothermal Inc.

Brgy. Bitin, Bay, Laguna

Tiwi Chemistry Laboratory

Philippine Geothermal Inc.

Tiwi, Albay, Philippines

Ms.Anita A. Peh

Tel.: 63-2-8458400

Fax: 63-2-8480629


Ms.Yolanda Cruzana

Tel.: 63-2-8458400

Fax: 62-52-4885039




Thailand Geochemistry Laboratory

Department of Geological Sciences

Faculty of Science

Chiang Mai University

Chiang Mai, Thailand

Mr. Pongpor Asnachinda

Fax:. 66-53-892261

66-53-892274


Uganda Geological Survey and Mines Department

Plot 21-29 Johnstone Road

Entebbe, Uganda

Mr. Godfrey Bahati

Tel.: 256-41-320559/320656

Fax: 256-41-320364

E-mail: [email protected] or [email protected]




Geothermal Laboratory Procedures_Edition 2003

- Page 227 -

ANNEX B

2003 IAEA INTER-LABORATORY COMPARISON OF

GEOTHERMAL WATER CHEMISTRY

LIST OF REFERENCE LABORATORIES


China Analytical Laboratory

Beijing Research Institute of Uranium

Geology

Xiaoguan Dongli 10

Anwai, Beijing, 100029

Mr. Wang Zhiming

Tel.:. +86-10-64914830

Fax: +86-10-64917143



- Page 228 -

El Salvador Laboratorio Geoquimico

LaGeo, S.A. de C.V.

Km 11 ½ Carretera al Puerto de la Libertad, Colonia Utila, Nueva San Salvador, La Libertad, El Salvador, Centro America

Mr. Roberto Renderos

Geochemistry Lab

LaGeo S.A. de C.V.

Tel.: (503) 211-6745

Fax: (503) 211-6743


Iceland

Iceland GeoSurvey

Grensasvegur 9

IS-108

Reykjavik, Iceland

Mr. Halldor Armannson

Tel.: 354-528-1500

Fax: 354-528-1699


Pakistan Radiation and Isotope Application Division

Pakistan Institute of Nuclear Science and Technology (PINSTECH), P.O. Nilore,

Islamabad, Pakistan

Mr. Muhammad Rafiq Sheikh

Radiation and Isotope Application Division

Tel: 92-51-9290261; Fax: 92-51-9290275





- Page 229 -

Philippines PNOC EDC Central Chemistry Laboratory

Fort Bonifacio, Makati CIty, Metro Manila,

Philippines

Ms. Guima Urbino

Tel.: 63-2-8936001

Fax: 63-2-8401580 or 63-2-8401575



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