Elemental, My Dear Elemental, My Dear WatsonWatson

Paul MiddlesteadUniversity of Ottawa, G.G. Hatch Laboratory

For 20th Continuous Flow Conference, Davis, 2014

This talk is for new usersThis talk is for new users We will touch the basics on Elemental We will touch the basics on Elemental

analysersanalysers A mix bag of tricks and advicesA mix bag of tricks and advices Refer to manufacturer’s instruction manualsRefer to manufacturer’s instruction manuals

Only endorsed products are: Only endorsed products are: Rickards Rickards RedRed and and Rickards White !Rickards White !

Who/what is this talk Who/what is this talk for?for?

Meet my familyMeet my family

Combustion

EA

NCHS

TC/EA

Pyrolysis

HO

Largecapacity

S only TOC Stableisotopes

15000C12000C

Leco is the most popular manufacturer of Leco is the most popular manufacturer of elemental analysers. elemental analysers. EveryEvery department department has one or two of those accumulating dust.has one or two of those accumulating dust.

Static combustion using oxygen: not Static combustion using oxygen: not suitable for IRMS.suitable for IRMS.

Meet Grand PaMeet Grand Pa

•Elemental Analyser as an…instrument•Schematics•Autosamplers•Flash combustion•Chemicals & Configurations•Gas Chromatography•Thermal Conductivity Detector•Typical run

•Common problems•EA-IRMS

Let’s touch onLet’s touch on

Simultaneous determination of Nitrogen, Simultaneous determination of Nitrogen, Carbon, Hydrogen, Sulfur, OxygenCarbon, Hydrogen, Sulfur, Oxygen

Measuring range: 100 ppm to 100%Measuring range: 100 ppm to 100% Sample size: 0.1 to 1000 mg / 0.1 to 25 ulSample size: 0.1 to 1000 mg / 0.1 to 25 ul Detection limit: 10 ppmDetection limit: 10 ppm Accuracy: 0.3% - 0.02% absoluteAccuracy: 0.3% - 0.02% absolute

EA as an …. instrumentEA as an …. instrument

CE instruments (Carlo Erba) models CE instruments (Carlo Erba) models 1108, 1110, NA 1500, NA 2100, Flash 1108, 1110, NA 1500, NA 2100, Flash 1112, Flash 20001112, Flash 2000

Costech Model ECS4010Costech Model ECS4010 Elementar cube familyElementar cube family Eurovector models EuroEa3028-HT, Eurovector models EuroEa3028-HT,

Ea3024-IRMS, pyrolysis modelEa3024-IRMS, pyrolysis model Sercon-Integra2 Sercon-Integra2 TC\EA ThermoTC\EA Thermo ……

Manufacturers, models Manufacturers, models blablablablablabla

EA : Bulk analysis of EA : Bulk analysis of NCHS/ONCHS/O

Organic compoundsOrganic compounds PharmaceuticalsPharmaceuticals OrganometallicsOrganometallics PetrochemicalsPetrochemicals Gasoline & fuelsGasoline & fuels GraphiteGraphite Carbides & nitridesCarbides & nitrides

Metals & alloysMetals & alloys PolymersPolymers ExplosivesExplosives HydrocarbonsHydrocarbons SoilsSoils Coal & cokeCoal & coke LiquidsLiquids

In short, you can combust your grandmother!

Ref gas 1

Elemental Analyser

(CNS)(OH)

Interface Isotope Ratio Mass Spectrometer

HeRef gas 2 2 m

Typical EA setup with Typical EA setup with IRMSIRMS

EA pictureEA picture

Elemental Analyser Elemental Analyser SchematicSchematic

TCD

CombustionChemicals1020C

ReductionChemicals650C

Gas chromatographyColumn in oven

Thermal Conduc-tivity Detector

Autosampler

N2

H2O

CO2

SO2

HeO2

WaterTrap EA line

out

Found the problem with Found the problem with the previous slide?the previous slide?

A beer if you do…A beer if you do…(5 seconds)(5 seconds)

Elemental Analyser Elemental Analyser SchematicSchematic

TCD

CombustionChemicals1020C

ReductionChemicals700C

Gas chromatographyColumn in oven

ThermocoupleDetector

Autosampler

N2

H2O

CO2

SO2

HeO2

WaterTrap EA line

out

A cold A cold Rickard’s RedRickard’s Red for me please.for me please.

1.1. Sample/Std is weighed and wrapped in tin Sample/Std is weighed and wrapped in tin foil, placed in culture tray/autosamplerfoil, placed in culture tray/autosampler

2.2. Sample drops is flash-combusted in OSample drops is flash-combusted in O22 in in He stream, causing rapid cracking and He stream, causing rapid cracking and oxidation of gases stoichiometrically oxidation of gases stoichiometrically equivalent to their elemental components, equivalent to their elemental components, some gas oxides need to be reduced before some gas oxides need to be reduced before obtaining final products (Nobtaining final products (N22, CO, CO22, H, H22O, SOO, SO22) ) i.e. oxidation and reducing reactions i.e. oxidation and reducing reactions involvedinvolved

Typical Analysis Procedure for Typical Analysis Procedure for EAEA

Typical Analysis Procedure for Typical Analysis Procedure for EAEA

3. Separation of gases by gas chromatography or chemical column traps

4. Detection by thermal conductivity detector (TCD) or IRMS.

5. Curve made from weighing certified stds (for isotope and/or quantitative measurements)

Some torture tools…Some torture tools…

Well well, got culture?Well well, got culture?

SSuuppeerr ssiizzee mmee

MAIS C’EST IMPOSSIBLE!MAIS C’EST IMPOSSIBLE!

C’EST FANTASTIQUE!C’EST FANTASTIQUE!

Filters? Careful!

Not flat pleaseNot flat please

Autosamplers (AS200)Autosamplers (AS200)

Zero BlankZero Blank

Zero Blank modifiedZero Blank modified

Special tools requiredSpecial tools required

ECS 4010

Take 20 minutes to study the gas schematics of your

instrument

Take 20 minutes to study the gas schematics of your

instrument

Be good to yourselfBe good to yourself

Sample droppingSample dropping

0 10 30 40

START

Sample drops

Combustion starts Injected O2Flash should occurwithin 2-3 secondsof being dropped

20

seconds

• PLATINUMPLATINUM: Absorbs much of the heat of the : Absorbs much of the heat of the reactor before passing it on to the sample, slowing reactor before passing it on to the sample, slowing down reactiondown reaction

• ALUMINIUMALUMINIUM: Supplies good oxidation flash and : Supplies good oxidation flash and prime sample ignition but does not melt or mix prime sample ignition but does not melt or mix with the sample thus does not promote inner with the sample thus does not promote inner oxidationoxidation

• SILVERSILVER: Melts at 960: Melts at 96000C, does not take part in the C, does not take part in the combustion, retains trace of carbon when in combustion, retains trace of carbon when in molten statemolten state

• TINTIN: Inexpensive & takes active part in process. : Inexpensive & takes active part in process. Melts at 235Melts at 23500C with very low enthalpy, intermixes C with very low enthalpy, intermixes with organic and inorganic substances, expedites with organic and inorganic substances, expedites the final oxidation reactionthe final oxidation reaction

Why you Tin man?Why you Tin man?

CC CO CO2 2 COCO22

Let’s get crackingLet’s get cracking

HH HH22OO HH22OO

SS SO SO2 2 + SO+ SO33 SOSO22

Combustion tube

Reduction tube

NN N N2 2 + NxOx+ NxOx N N22

Chemicals and Chemicals and ConfigurationsConfigurations

• System should be optimized for element(s) to be analyzed

• One-tube system: both oxidant catalyst and reducing chemicals in one tube; usually used if S is to be analyzed

• Two-tube system: one tube for oxidant, one tube for reducing chemicals; usually used for N, NC or NCH

• Chemical traps: Mg Perchlorate or Anhydrone will trap H2O, and Carbosorb will trap CO2 (and SO2)

ConfigurationConfigurationCNCN

ConfigurationConfigurationSS

Small is Small is beautifulbeautiful

Using grinding tools and diluted Nitric acid, one can re-use Using grinding tools and diluted Nitric acid, one can re-use combustion and reduction tubescombustion and reduction tubes

More torture toolsMore torture tools

Gas chromatographic columns will separate different Gas chromatographic columns will separate different components according to their polarity and molecular components according to their polarity and molecular size.size.

Factors influencing the quality of the chromatography: Factors influencing the quality of the chromatography: column length, size of packing, tube diameter, column length, size of packing, tube diameter, stationary stationary phase type, flow rate, temperature.phase type, flow rate, temperature.

Packed column:Packed column: packed polymer beads, different sizes packed polymer beads, different sizes available. High capacity , low resolution.available. High capacity , low resolution.

Capillary column:Capillary column: small capillary with polymeric film on small capillary with polymeric film on inner wall. High resolution, low capacity. inner wall. High resolution, low capacity.

Deactivated fused silica is free of adsorption problems Deactivated fused silica is free of adsorption problems encountered with most packings or capillaries columns.encountered with most packings or capillaries columns.

Gas ChromatographyGas Chromatography

Gas Separation/ GCGas Separation/ GC

He + N2 , CO2 , H2O , SO2 + He

He + SO2 + H2O + CO2 + N2 + He

INCREASING POLARITYOF GASES

What after we separate?What after we separate?

He + SO2 + H2O + CO2 + N2 + He

DETECTOR

TIME

DE

TE

CT

OR N2

CO2

SO2

H20

Gas Separation / Purge & Gas Separation / Purge & TrapTrap

TCD

SO2 H2O CO2

Thermal conductivity detector (TCD)Thermal conductivity detector (TCD) Heated filament from which heat is removed at Heated filament from which heat is removed at a constant rate by He gas stream. Change in a constant rate by He gas stream. Change in heat transfer is caused by presence of analyte heat transfer is caused by presence of analyte molecules with different thermal conductivities molecules with different thermal conductivities than He. Relatively low sensitivity, excellent than He. Relatively low sensitivity, excellent range and linearity. Non-destructive.range and linearity. Non-destructive.Electron capture detector (ECD)Electron capture detector (ECD)Electrons are captured by organic species in Electrons are captured by organic species in ionized carrier; used for trace sulfur ionized carrier; used for trace sulfur determination.determination.Isotope Ratio Mass Spectrometer (IRMS)Isotope Ratio Mass Spectrometer (IRMS)

DetectorsDetectors

Typical output of EA, text Typical output of EA, text bookbook

N2

CO2

H2OSO2

Balance: Get the best Balance: Get the best

A 0.01mg readability A 0.01mg readability translates in an error of translates in an error of 0.25% on a 2 mg sample 0.25% on a 2 mg sample (on 100% carbon)(on 100% carbon)

BalanceBalance

IAEA (and NIST) IAEA (and NIST) standardsstandards

Links available on Isogeochem

Best : %N, Best : %N, 1515N, %C, N, %C, 1313CC

Test different materials and pray Test different materials and pray

Make your own:Make your own:

CaffeineCaffeine

L-glutamic acidL-glutamic acid

Mixtures such as sucrose + potassium nitrateMixtures such as sucrose + potassium nitrate

Mix in solution of natural + Mix in solution of natural + enriched/depleted material then dried, enriched/depleted material then dried, powdered, sievedpowdered, sieved

STD: Making it on your STD: Making it on your own…own…

STD: Not making it on your STD: Not making it on your own…own…

Can also contact other university labs to Can also contact other university labs to buy or obtain their internal standards. buy or obtain their internal standards.

STD: Not making it on your own…STD: Not making it on your own…

ARNDT SCHIMMELMANNIndiana University http://mypage.iu.edu/~aschimme/hc.htm

Calculation MethodsCalculation Methods

1. K-Factor (Single point calibration with blank substraction)

Calculated % = K * (Area unk – Area blk)Weight unk

Where K = Weight std * Theor std %Area std - Area blk

Calculation MethodsCalculation Methods

2. Linear Fit (Least square linear regression)

Calculated % = m * Area unk + b Weight unk

Peak Area

Wt *

Th

std

%

Calculation MethodsCalculation Methods

3. Quadratic Fit (Least square quadratic regression)

Calculated % =

a * Area unk2 + b * Area unk + c Weight unk

Peak Area

Wt *

Th

std

%

An update…An update…

Most elemental analysers manufacturershave considerably refined their calculation methods, with more complex algorithms, low-high ranges and statistical tools.

Leak check (1)Leak check (1)

EA

Pressure check

•Cap exit port•Increase P of He to 1.3 bar, wait 3 minutes•Close regulator•Pressure gauge should not move for 5 minutes

EA

Flow check (requires electronic mass flow controller)

•Cap exit port•Monitor flow for 3 minutes•Flow should drop to 0 ml/min

Leak check (2)Leak check (2)

EA Inter-face

Leak check with IRMS

•EA has been leak checked•EA chemicals have outgassed (12 hours) •Tune to Ar (mass 40)•Should meet manufacturer’s requirements•Use Ar cylinder to hunt

MS

Ar

Elemental Analyser Schematic for Elemental Analyser Schematic for IRMSIRMS

TCD

Combustion tube Reduction tube

Water trap

Gas chromatographyColumn

ThermocoupleDetector

Autosampler

To MS

N2 CO2InterfaceDiluter & ref gas

Water is removed via Mg Perchlorate/sicapent Water is removed via Mg Perchlorate/sicapent traptrap---water and mass spectrometer ---water and mass spectrometer do not mixdo not mix--------

Configuration should be optimized for gas of Configuration should be optimized for gas of interestinterest

Leak free (mass 28 & 40, use Argon as leak probe)Leak free (mass 28 & 40, use Argon as leak probe) Low and stable background (mass Low and stable background (mass 2828, 18, 40, , 18, 40, 4444)) Dynamic range must be respected, do use target Dynamic range must be respected, do use target

beambeam Best sequence is carefully planned ie known Best sequence is carefully planned ie known

concentration of samplesconcentration of samples Garbage in……Garbage outGarbage in……Garbage out

Considerations for EA-IRMSConsiderations for EA-IRMS

Some useful infoSome useful infoLab No. Sample type Nitrogen Carbon Hydrogen Sulphur C/N Comments

97-256-010 Adult mysids 10,20 50,97 na na 5,00 Whall JD, Trent U.

97-220-003 Amphipods 6,81 33,20 5,66 0,00 4,88 Pastershank G., U of O/ Biology

97-256-004 Chironomids 8,98 37,23 na na 4,15 Whall JD, Trent U.

97-256-014 Clam 12,30 48,91 na na 3,98 Whall JD, Trent U.

97-220-004 Clam muscle 11,26 43,41 6,77 1,10 3,85 Pastershank G., U of O/ Biology

97-220-005Clam shell

0,05 11,91 0,19 0,00231,6

3Pastershank G., U of O/ Biology

97-220-018 Cragon (shrimp) 10,03 37,22 5,91 0,00 3,71 Pastershank G., U of O/ Biology

97-220-020 Diatom 0,00 0,74 0,09 0,00 N.A. Bad trace

97-220-002 Egg white 11,85 45,83 6,93 1,14 3,87 Pastershank G., U of O/ Biology

97-220-001 Egg yolk 5,41 62,69 9,73 0,00 11,59 Pastershank G., U of O/ Biology

97-220-009 Fish bone 6,43 19,53 3,51 0,00 3,04 Pastershank G., U of O/ Biology

97-220-008 Fish eye 12,90 48,70 7,05 2,13 3,77 Pastershank G., U of O/ Biology

97-220-013 Fish fin 10,01 34,36 5,35 0,00 3,43 Pastershank G., U of O/ Biology

97-220-014 Fish gill 13,28 47,10 7,06 0,00 3,55 Pastershank G., U of O/ Biology

97-220-015 Fish gut content 9,56 44,88 7,07 1,13 4,69 Pastershank G., U of O/ Biology

Best are quartz filters; they are stable. However Best are quartz filters; they are stable. However they are more expensive and offer less choice.they are more expensive and offer less choice.

Silver filters are great too.Silver filters are great too. Mostly glass filters, cheap, huge choice.Mostly glass filters, cheap, huge choice. How much to use? How much to use?

Filters, we can do that!Filters, we can do that!

Filters, we can do that!Filters, we can do that!

Area = *R2

In this case, a punch is about 16mm2 and our whole filter is about 1490mm2 .Our punch hole is roughly 1% of the filter.

Sediment contaminationSediment contamination

Inorganic Carbon

Average 13C: 0‰

= Total CarbonOrganic Carbon

Average 13C: -25‰

0% + 100% = -25 ‰1% + 99% = -

24.75 ‰5% + 95% = -23.75 ‰10% + 90% = -22.50 ‰50% + 50% = -12.5 ‰

Detection Limit? Hmmmm…Detection Limit? Hmmmm…

Every manufacturer has them, frankly they are all similar.In the end, you want an instrument that is linear with a decent sensitivity and a nice sample peak.Your source should be adjusted accordingly and you may have to sacrifice sensitivity in order to obtain stability and linearity. Hence, the detection limit may change according to the source parameters, the EA configuration and the condition of the chemicals.Be conservative.

Optimal amount for meOptimal amount for me

% Nitrogen Wt required

100 0.1mg

10 1.0mg

5 5mg

2 7mg

1 10mg

0.1 100mg

0.001 Yeah, right!

Optimal amount of Nitrogen: 0.1mg

Open split, magical stuffOpen split, magical stuff

He + CO2 + N2 + He

EA 100 ml/min

Fused silica capillary100 um, 2m, insertedabout 30cm in EA line,0.4 ml/min going intosource of IRMS

2mm or 1/16” SSline from EA

In real life…Open splitIn real life…Open split

EA

IRMSRef 1

Ref 2

He

Ref 3

The joy of sniffing EA onlyThe joy of sniffing EA only

Mass spectrometer outputMass spectrometer output

TCD output from EATCD output from EA

MagnetMagnetPeakjumPeakjumpp

N2

CO2

Mass 28, 29Mass 44,45,46

The joy of sniffing, totalThe joy of sniffing, total

Mass spectrometer outputMass spectrometer output

TCD output from EATCD output from EA

MagnetMagnetPeakjumPeakjumpp

N2

CO2

Mass 28, 29Mass 44,45,46

Masses 28 & 29 Masses 44, 45 & 46

To dilute or Not to dilute?To dilute or Not to dilute?

A useful suggestion…A useful suggestion…

I strongly recommend that you create a basic document for your users explaining

the limits and pitfalls of EA-IRMS analysis, this will save you (and your users) an

enormous amount of time.

Removing inorganic carbon is not trivial.Removing inorganic carbon is not trivial.

Alkalies (Sodium, Potassium, Calcium) are Alkalies (Sodium, Potassium, Calcium) are difficult to combust, catalist is definitively difficult to combust, catalist is definitively required to bind and help with oxydation.required to bind and help with oxydation.

Oxygen contribution to Oxygen contribution to 3434S is still a S is still a problem, especially with organic samples. problem, especially with organic samples.

Some unresolved issues Some unresolved issues with EAwith EA

Last suggestion and Last suggestion and only Official only Official

EndorsementEndorsement

The only product fully and officially endorsed by the author is:

Rickard’s White Rickard’s White

Thank youThank you

My thanks to:

Wendy Abdi, Nik Binder, Fred Longstaffe, Scott Hughes, Gilles St-Jean, Peter Stow and Patricia Wickham for the use of material, brain power and time …