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DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation1
Preparation of Liquid Samples
2009 Denver X-Ray Conference
Larry G. AriasProject Manager XRF Software / Manager XRF-US ApplicationsBruker AXS Inc. – Madison, WIlarry.arias@bruker-axs.com
July-20092009 DXC Liquid Preparation2
Basic Preparation of Liquid Samples
Pour sample into plastic cellFit polymer film to end of cellInvert cellPunch vent hole to allow for expansion
Page 2
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation3
Considerations for liquid preparation
Selection of sample cellEasy to assembleFits sample holders for spectrometerAppropriate for spectrometer opticsAppropriate for type of sample
Selection of polymer filmDurability (from handling and exposure to x-rays)Resistant to chemical attack from sampleGood transmission of the energies to be measuredContaminates in the polymer film
Effective layer depth for all lines being measuredDon’t want intensities to change by volume of sample measured
Laboratory practicePreparing samplesHandling filmHandling cells
Mechanics of preparing samples
July-20092009 DXC Liquid Preparation4
Select a Sample Cell That Fits the Sample Holder
Many sample holders have removable springs to keep samples stationary
Avoid using these springs wheneverpossibleContamination of holder by liquidExtraneous radiation from metal plate for higher energy lines
Centering rings or centering devices are available for all sample holders
Hold sample cell over cup opening without the need of a spring
Select a sample cell with inside diameter just larger than diameter of opening in cup
Helps prevent sagging of film
Page 3
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation5
Types of X-Ray Spectrometer Optics
Tube below optics(Inverted optics)• Ideal for liquids• Gravity works in our favor
because analyzed surface is facing down
Tube above optics(Normal optics)• Not ideal for liquids• Working against gravity because
analyze surface is facing up
July-20092009 DXC Liquid Preparation6
Closed Cells (used with tube below)
Cell with large sleeveSleeve is used to hold film firmly in place
Cell with small clamping ring and optional collar
Collar is used to hold film loosely in placeSmall clamping ring clamps film firmly to cell
Good for:• Samples that flow well• Samples that are not volatile
Page 4
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation7
Closed Cells - Top View
Vent area on back of cellArea where cell is very thin to allow easy ventingPuncture with push-pin or other sharp object
Snap post™Cell has post which can be pushed in to vent cell“Snap post” is a trade mark of SPEX Certiprep
Most closed cells have a reservoir on top to catch expanding liquid
July-20092009 DXC Liquid Preparation8
Double Open Ended Cells 1 (tube below)
Cell with large sleeve and capSleeve is used to hold film firmly in placeVented cap placed on cell after filling with sample
Good for:Samples that do not flow wellVolatile samples
Page 5
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation9
Double Open Ended Cells 2 (tube below)
Cell with small identical clamping ringsSmall clamping ring clamps film firmly to cellSecond clamping ring can be used to close cell with polymer film or micro-porous film on top side
Optional vented caps are available
Good for:Samples that do not flow wellVolatile samples
July-20092009 DXC Liquid Preparation10
Micro X-Cells (tube below)
Available from SPEX CertiPrep®
Aperture of 6.3 mmFits standard 31 mm sample holderCan be fitted with standard 7 X 13 mm serum bottle closure
Allows pre-filling with inert gas for air sensitive samples
Collar to loosely hold film to cellCell with film snaps into hole of 31 mm bottom to firmly clamp film in placeClamping ring can be used to close top of cell with polymer film, micro-porous film, or serum bottle closure
Good for:Small amounts of sample
Page 6
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation11
SpectroMicroTM Cells (tube below)
Clamping ring to firmly clamp film to bottom of cellVented cap to close top of cell
Apertures of 6, 10, 15 and 20 mmFits standard 31 mm sample holderHas integrated funnel for easy sample loading
SpectroMicroTM is a trade mark of Chemplex Industires
Good for:Small amounts of sample
July-20092009 DXC Liquid Preparation12
Special Cell Inserts for Tube Above Optics
Available from SPEX Certiprep®
Bubble-Free Cell InsertFits in standard 40 mm cellAir bubbles end up trapped in area shown by red circles in cut away view
Page 7
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation13
Films for Liquid Sample Cells
Liquid sample cells must be covered with a thin film which acts as the sample window
Film should be free from contaminates which are the same as any elements to be determined at low levels.Film must have reasonably high transmission of the X-ray energies to be measured.Film must contain the liquid without deterioration
Generally speakingChoice of film may be dictated by type of sample to analyzed
To avoid chemical attack which would weaken the film
Thicker films are more durable than thinner films Safer to use
Thicker films absorb more of the lower X-ray energies produced by the sample
Lower performance for low energy lines (low atomic number elements)
July-20092009 DXC Liquid Preparation14
Contaminates in Films
Every film can have contaminatesThese contaminates become an issue when:
One of them is the same as an element being measuredAn emission line from the contaminate interferes with a line being measured
Contamination levels can be different between films with different lot numbersPurchase film in large quantities
More likely to be from the same Lot numberAll boxes of film will have the same level of contamination
If contaminates are an issueUse “Blank Subtraction”Make New Calibrations each time film is purchased
Page 8
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation15
Checking Films for Contaminates
Each time new film is received it should be tested for contaminates before using it• Film is not manufactured for XRF use• Film is typically not pre-tested by supplier• Manufacturer of film can change process at any time
Preferred method:• Allows accounting for system and sample contaminates
2-theta scan on a blank sample in a vacuum path(Example: Pressed cellulose, wax, etc)2-theta scan on same blank sample with a piece of film in front of itOverlay the two scans
Alternate method:• Does not account for system or sample contaminates
2-theta scan on a blank sample in helium atmosphere(Example: Distilled water, Base Oil, etc)View the scan
July-20092009 DXC Liquid Preparation16
Contaminates in Polyester (Mylar®) Films
Ca and P are significantTraces of Sb and SiTypical supplier reports:
Ca, P, Sb, Fe, Zn
01
23
4
KC
ps
Ca
KA1
111.5 112 112.5 113 113.5 114. 3
° 2Th LiF200
00.
10.
20.
30.
40.
50.
60.
70.
80.
91
KC
ps
Sb L
A1
116 116.5 117 117.5 118 118.5
° 2Th LiF200
01
23
45
6
KC
ps
P K
A1
88 89 90 91
° 2Th PET
00.
10.
20.
30.
40.
50.
60.
7
KC
ps
Si K
A1
108 109 110
° 2Th PET
Mylar® is registered trademark of E.I. duPontde Nemours & Co. for its polyester film
Page 9
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation17
Contaminates in Polyimide (Kapton®) Films
Ca and P are fairly significantTypical supplier reports: Phosphate based surface coating
00.
10.
20.
30.
40.
50.
60.
70.
80.
91
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
KCps
P K
A1
88 89 90 91
° 2Th PET
00.
10.
20.
30.
40.
50.
60.
70.
80.
91
1.1
1.2
1.3
1.4
1.5
1.6
1.7
1.8
1.9
2
KCps
Ca K
A1
112 112.5 113 113.5 114
° 2Th LiF200
July-20092009 DXC Liquid Preparation18
Contaminates in Polycarbonate Films
Traces of SiSupplier reports “Unknown”
0.2
0.3
0.4
0.5
0.6
0.7
KCps
Si K
A1
108 109 110
° 2Th PET
Page 10
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation19
Contaminates in EtnomTM Films
Traces of Si and PSupplier reports: Si, Ca, P, Zn, Sb
00.
10.
20.
30.
40.
50.
60.
81
23
KC
ps
Si K
A1
105 106 107 108 109 110 111 112 113
° 2Th PET
00.
010.
020.
040.
060.
080.
10.
20.
30.
4
KC
ps
P
KA
188 89 90 91
° 2Th PET
July-20092009 DXC Liquid Preparation20
Contaminates in Polypropylene Films
Traces of S, Si and AlTypical supplier reports: Ca, P, Fe, Cu, Zr, Ti and Al
0.3
0.4
0.5
0.6
0.7
0.8
0.9
KCps
S K
A1
74.6 75 75.5 76 76.5 77
° 2Th PET
0.2
0.3
0.4
0.5
0.6
0.7
KCps
Si K
A1
108 108.5 109 109.5 110
° 2Th PET
0.06
0.08
0.1
0.2
0.3
0.4
KCps
Al K
A1
143 144 145 146
° 2Th PET
Page 11
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation21
Selection of Film for Transmission Properties
Thickness of Film is directly proportional to:Safety of use – less likely to break, leak, or sagEase of handlingAbsorption of lower energy X-rays (low atomic number elements)
Average atomic number of film is directly proportional to its absorption:
Films with Oxygen or Nitrogen have higher absorption then Carbon-Hydrogen films
July-20092009 DXC Liquid Preparation22
X-ray Transmission by Films of Same Thickness
10
20
30
40
50
60
70
80
90
100
2 3 4 5 6 7 8 9 10 11 12
Wavelength in Angstroms
%-T
rans
mis
sion Polypropylene 6.0µ
Polycarbonate 6.0µEtnom-S 6.0µPolyimide 6.0µMylar 6.0µ
NaMgAlSiPSCl
BrRbZrMoRh
K-lines
L-lines
Etnom-STM is a Trade Mark of Chemplex IndustriesMylar® is registered trademark of E.I. duPont de Nemours & Co
Page 12
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation23
X-ray Transmission for Common Films
10
20
30
40
50
60
70
80
90
100
2 3 4 5 6 7 8 9 10 11 12
Wavelength in Angstroms
%-T
rans
mis
sion
Polypropylene 4.0µPolypropylene 6.0µPolypropylene 12.0µPolycarbonate 5.0µPolyimide 7.5µMylar 1.5µMylar 2.5µMylar 3.6µMylar 6.0µ
NaMgAlSiPSCl
BrRbZrMoRh
K-lines
L-lines
Etnom-STM is a Trade Mark of Chemplex IndustriesMylar® is registered trademark of E.I. duPont de Nemours & Co
July-20092009 DXC Liquid Preparation24
Chemical Resistance of Films
Film suppliers have excellent detailed information on chemical resistance in their catalogs and on their web sites – Use this resource
Always test films before using themPrepare a sample and let sit for 30 – 60 minutes in same orientation the sample will be measuredCheck the film for wrinkles, sagging and leaks
YesYesYesEtnomTM
YesYesNoPolyimide ®
YesNoYesMylar®
NoNoYesPolycarbonate
NoYesYesPolypropylene
HydrocarbonsBasesAcids
General rules for chemical resistance of films
Page 13
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation25
Films are available in several physical forms
Continuous Rolls
Pre-cutCircles
Pre-CutSquares
Mounted on a Carrier Frame (1)
(1) Available from Chemplex Industries
July-20092009 DXC Liquid Preparation26
Analyzed Layer and Infinite Thickness
No excitation of atoms in the upper part of the sample
Center part of the sample is excited but the emitted radiation is absorbed within the sample so it never reaches the detector
Fluoresced radiation that is actually measured comes from a layer near the sample surface
Called the Analyzed Layer
Thickness of Analyzed Layer is proportional to the energy of the line being measured
Thickness of Analyzed Layer is inversely proportional to average atomic number of sample
A sample is considered Infinitely Thick when its thickness is ≥ the Analyzed Layer depth
Page 14
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation27
Non-Infinitely Thick Samples
Samples are non-infinitely thick when:
sample thickness < analyzed layer
Intensities are no longer a function of just concentrations• Intensities vary by
o Concentration of analyte
o Thickness of sample
Analyzed Layer
Sample Thickness
July-20092009 DXC Liquid Preparation28
Handling Non-Infinitely Thick Samples
Non-infinitely thick samples can be handled by
Measure a line with a lower energyLα instead of Kα
Mα instead of Lα
Use an Internal Standard technique
Use a Heavy Element Absorber technique
Weigh each sample into the cell to maintain a constant mass
Usually ± 0.1 gram
%
ISIIS
Page 15
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation29
Infinite thickness for K-lines (Oil & Water)
16.820.610.54As KA133As
13.516.59.887Ge KA132Ge
10.813.29.252Ga KA131Ga
8.710.88.639Zn KA130Zn
7.28.78.048Cu KA129Cu
5.76.97.478Ni KA128Ni
4.55.46.931Co KA127Co
3.64.26.404Fe KA126Fe
2.73.35.899Mn KA125Mn
2.12.55.415Cr KA124Cr
1.61.94.952V KA123V
1.21.44.511Ti KA122Ti
0.660.753.692Ca KA120Ca
0.480.543.314K KA119K
0.240.272.622Cl KA117Cl
Water SampleInfinite thickness
(mm)
Oil SampleInfinite thickness
(mm)
Energy(keV)
LineZEl
Most cells hold about 1 cm (10 mm) of liquid
July-20092009 DXC Liquid Preparation30
Infinite thickness for L-lines (Oil & Water)
18.022.210.83Bi LA183Bi
16.520.410.55Pb LA182Pb
13.817.19.978Hg LA180Hg
10.813.29.175Ir LA177Ir
9.011.08.646Re LA175Re
8.19.98.397W LA174W
7.59.08.146Ta LA173Ta
6.68.17.899Hf LA172Hf
3.03.66.056Gd LA164Gd
1.21.44.464Ba LA156Ba
0.630.693.604Sb LA151Sb
0.540.603.444Sn LA150Sn
0.420.453.133Cd LA148Cd
0.360.392.984Ag LA147Ag
0.170.182.294Mo LA142Mo
Water SampleInfinite thickness
(mm)
Oil SampleInfinite thickness
(mm)
Energy(keV)
LineZEl
Most cells hold about 1 cm (10 mm) of liquid
Page 16
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation31
Preparation Hints
ASTM D7343-07 Standard Practice for Optimization, Sample Handling, Calibration, and Validation of X-ray Fluorescence Spectrometry Methods for Elemental Analysis of Petroleum Products and LubricantsProvides concise guidelines for
• Sample handling
• Sample preparation
• Sample stability
• Instrument validation
• Detailed sample preparation procedures
• Measurement of standards and samples
• Calibration
• Validation
Every technician dealing with the preparation of liquids should read and understand this Standard
July-20092009 DXC Liquid Preparation32
Preparation Hints
Wear clean gloves, this will minimize contamination of sample cell and film by oils from hands
Ensure work surface is clean
Use clean lint free tissues on the work surface
Use sample cells with the smallest diameter opening that will cover the openings in the sample holders
Avoid touching the inside of sample cells
Handle film by edges and avoid touching the analyzed part of the film (portion to be X-rayed)
When placing a sample cell film side done on the work surface ensure it is on a clean lint free tissue
Page 17
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation33
Preparation Hints
When using closed cells punch vent hole immediately after attaching film.
Important for samples with high vapor pressure
Prevents bulging of film from pressure build up
Liquids that do not flow well can usually be heated in an oven at around 45ºC to improve their flow characteristics
After preparing samples allow the prepared cell to sit on a clean lint free tissue for about 30 seconds before placing into a sample holder
Put sample cell with film side down on tissue
Check tissue for signs of leakage when lifting sample
July-20092009 DXC Liquid Preparation34
Preparation Hints
Ensure that the film on an assembled cell is free from any wrinkles• Discard and remake if not
Ensure that the film on an assembled cell is free from any dimples along the edges• Can displace sample• Can cause leaks• Discard and remake
Page 18
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation35
Preparation Hints
When using precut sheets of film try to keep film in contact with the separating paper to avoid static build up• The paper also serves as a clean
surface to place the assembled cell onto
Ensure sample cell is sitting properly in the sample holder
Flat against the bottomCentered on cup opening
Ensure that none of the film extends outside of the sample holder
July-20092009 DXC Liquid Preparation36
Preparation of Closed Cell With Sleeve
Sample cellSleeve to clamp film to top of cellPieces fit together in only one orientation
Place sample cell on table with opening upPlace sample into cell to fill line• Usually about ½ to ⅔ full
Or weigh constant mass of sample into cell on a balance• Usually ± 0.1 gram
Page 19
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation37
Preparation of Closed Cell With Sleeve
Hold film over top of cell• Take care not to touch film in analyzed area
Seal film to cell using sleeve• Ensure sleeve is in correct orientation• Push sleeve down with steady even pressure• Do not distort the sleeve by squeezing too tightly
Ensure that• Sleeve does not rise above the body of cell• Film is tight and free from wrinkles
July-20092009 DXC Liquid Preparation38
Preparation of Closed Cell With Sleeve
Invert cell on clean surface (film side down)Punch vent hold in top of cell
Place sample on clean tissue for about 30 seconds
Check tissue for dampness when lifting sample to load in sample holder
Page 20
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation39
Preparation of Closed Cell With Optional Collar & Clamping Ring
Sample cellOptional loosely fitting collar to pre-fix film to cellClamping Ring to fix film to cell
Place sample cell on table with opening upPlace sample into cell to fill line• Usually about ½ to ⅔ full
Or weigh constant mass of sample into cell on a balance• Usually ± 0.1 gram
July-20092009 DXC Liquid Preparation40
Preparation of Closed Cell With Optional Collar & Clamping Ring
Hold film over top of cell• Take care not to touch film in analyzed area
Pre-fix film to cell using the thin collar ring• This is an optional step
Seal film to cell using clamping ring• Push clamping ring down with steady even pressure• Do not distort the clamping ring by squeezing too
tightly
Page 21
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation41
Preparation of Closed Cell With Optional Collar & Clamping Ring
Hold film over top of cell• Take care not to touch film in analyzed area
Seal film to cell using clamping ring• Push clamping ring down with steady even pressure• Do not distort the clamping ring by squeezing too
tightly
Ensure that• Clamping ring does not rise above the body of cell• Film is tight and free from wrinkles
Alternate method using just the clamping ring:
July-20092009 DXC Liquid Preparation42
Preparation of Closed Cell With Optional Collar & Clamping Ring
Invert cell on clean surface (film side down)Punch vent hold in top of cell
Place sample on clean tissue for about 30 seconds
Check tissue for dampness when lifting sample to load in sample holder
Page 22
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation43
Preparation of Double Open Ended CellWith Sleeve and Vented Cap
Place sample cell on table in correct orientation(film side up) Hold film over top of cell• Take care not to touch film in analyzed area
Seal film to cell using sleeve• Ensure sleeve is in correct orientation• Push sleeve down with steady even pressure• Do not distort the sleeve by squeezing too tightly
Smaller diameter barrel is cellLarger diameter barrel is sleevePieces fit together in only one orientation
July-20092009 DXC Liquid Preparation44
Preparation of Double Open Ended CellWith Sleeve and Cap
Place sample cell on table with opening up(film side down)Place sample into cell to fill line• Usually about ½ to ⅔ full
Or weigh constant mass of sample into cell on a balance• Usually ± 0.1 gram
Ensure that• Sleeve does not rise above the body of cell• Film is tight and free from wrinkles
Page 23
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation45
Preparation of Double Open Ended CellWith Sleeve and Cap
Attach vented cap to top of cell
Place sample on clean tissue for about 30 seconds
Check tissue for dampness when lifting sample to load in sample holder
July-20092009 DXC Liquid Preparation46
Preparation of Double Open Ended Cell With Clamp Rings and Vented Cap
Sample cellTwo identical clamping ringsOptional vented cap
Place sample cell on tableHold film over top of cell• Take care not to touch film in analyzed
area
Seal film to cell using clamping ring• Push clamping ring down with steady even pressure• Do not distort the clamping ring by squeezing too
tightly
Page 24
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation47
Preparation of Double Open Ended Cell With Clamp Rings and Vented Cap
Ensure that• Clamping ring does not rise above the body of cell• Film is tight and free from wrinkles
Place sample cell on table with opening up(film side down)Place sample into cell to fill line• Usually about ½ to ⅔ full
Or weigh constant mass of sample into cell on a balance• Usually ± 0.1 gram
July-20092009 DXC Liquid Preparation48
Preparation of Double Open Ended Cell With Clamp Rings and Vented Cap
Place sample on clean tissue for about 30 seconds
Check tissue for dampness when lifting sample to load in sample holder
Attach vented cap to top of cell
Page 25
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation49
Preparation of Double Open Ended Cell for Loose Powder using Micro-porous film
Fix film to cell as beforePlace cell on table with opening up(film side down)Place powder into cell
Hold micro-porous film over top of cell
Seal micro-porous film to cell using clamping ring• Push clamping ring down with steady even pressure• Do not distort the clamping ring by squeezing too tightly
July-20092009 DXC Liquid Preparation50
Preparation of Double Open Ended Cell for Loose Powder using Micro-porous film
Micro-porous film might extend out quite far• Could get trapped between top and bottom of sample
holder• Could cause sample cell to not sit flat in sample holder
Trim excess from micro-porous film before placing into sample holder
Page 26
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation51
Preparation of Double Open Ended Cell With Samples That do not Flow Well
Fix film to cell as beforePlace cell on table with opening up(film side down)
Put sample into cell
July-20092009 DXC Liquid Preparation52
Preparation of Double Open Ended Cell With Samples That do not Flow Well
Place piece of film on top of cell
Push excess film into cell
Hold cell firmly on clean flat surface and use rod to flatten the sample against the cell window• The rod should have a diameter of about 1-2 mm less
than the inside diameter of the cell
Page 27
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation53
Preparation of Double Open Ended Cell With Samples That do not Flow Well
Close cell with vented cap (optional step)
Check sample surface for defects
Close cell with film and make vent hole (optional step)
July-20092009 DXC Liquid Preparation54
Preparation of Micro X-Cells
Sample cell (barrel) with 6.3 mm I.D.Collar to loosely hold film to cellCell with film snaps into hole of 31 mm base to firmly clamp film in placeClamping ring can be used to close top of cell with polymer or micro-porous film
Stand cell on table so small diameter end is facing upHold film over opening in cellLoosely fix film to cell using collar
Page 28
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation55
Preparation of Micro X-Cells
Place base on table (analyzed surface down)Snap cell into bass to seal film to base
Place base on table (analyzed surface down)Place film on top of baseSnap cell into bass to seal film to base
Alternate method without pre-fixing film
July-20092009 DXC Liquid Preparation56
Preparation of Micro X-Cells
Orient assembled cell so opening is facing up
Place sample into cell
Page 29
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation57
Preparation of Micro X-Cells
Optional step• Seal top of cell with polymer film or micro-porous
film using the clamping ring
If top of cell was sealed with polymer film• Punch vent hole in film
NOTE: Serum bottle closure can be fitted to top of cell before adding liquid to allow injection of inert gas followed by injection of sample
July-20092009 DXC Liquid Preparation58
Preparation using Bubble Free Insert
Place Bubble Free insert into closed liquid sample cell as shownPlace liquid sample in the cell to within 0.5 to 1.0 mm of top rimFix film to top of cell using clamping ring(push down with steady even pressure)Invert cell and “jiggle” to force air bubble through center hole of cell so it becomes trapped when cell is placed film side up
Page 30
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation59
Small Amounts of Liquids on Filter Papers
Commonly referred to as “Dried Spot”techniqueSmall amounts of liquid (20 – 50 µL) are put on a suitable filter then allowed to dryMultiple applications of a sample can be made to increase the concentration levelsEspecially useful for light element analysis
Can be measured in vacuumNo absorption by heliumCan be measured without filmNo absorption by polymer film
Filter papers from:• BREITLÄNDER• Hydrophobic Ring Filters• BR XRF42/25• BR XRF50/32
July-20092009 DXC Liquid Preparation60
Na Calibration as Liquid versus on Filter Paper
Normal liquid calibration
Int. corrected
Cor
rect
ed In
tens
ity (K
Cps
)
Concentration (PPM)
0
0.01
0.02
0.03
0.04
0.05
0.06
0.07
0.08
0.09
0.10
0.11
0.12
0 100 200 300
Std Dev = 3 ppmSens = 3.465 kCPS/%LLD = 8.5 ppm
50 µL of sample on filter paper
Int. corrected
Cor
rect
ed In
tens
ity (K
Cps
)
Concentration (PPM)
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1.0
1.1
0 100 200 300
Std Dev = 4 ppmSens = 33.047 kCPS/%LLD = 1.0 ppm
Page 31
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation61
Int. corrected
Cor
rect
ed In
tens
ity (K
Cps
)
Concentration (PPM)
00.10.20.30.40.50.60.70.80.91.01.11.21.31.41.51.61.71.81.92.02.12.22.32.42.52.62.72.82.93.03.13.2
0 100 200
S Calibration as Liquid versus on Filter Paper
Normal liquid calibration
Std Dev = 0.4 ppmSens = 128.966 kCPS/%LLD = 0.5 ppm
50 µL of sample on filter paper
Int. corrected
Cor
rect
ed In
tens
ity (K
Cps
)
Concentration (PPM)
0
1
2
3
4
5
6
7
8
0 100 200
Std Dev = 0.6 ppmSens = 355.745 kCPS/%LLD = 0.2 ppm
July-20092009 DXC Liquid Preparation62
Sources of Liquid Preparation Supplies
Chemplex Industries, Inc.2820 SW 42nd AvenuePalm City, FL 34990(800) 424-3675www.chemplex.com
Premier Lab Supply, Inc.2714 S.W. Edgarce StreetPort ST. Lucie, FL 34953(772) 873-1700www.premierlabsupply.com
Somar International, Inc.P.O Box 194759610 Prototype CtReno, NV 89511(775) 356-9300somar115@aol.com
SPEX CertiPrep203 Norcross AvenueMetuchen, NJ 08840(800) LAB-SPEX Ext 465www.spexcsp.com
Tech Ref Inc.2051 E. Cerritos Ave., Ste. FAnaheim, CA 92806 (800) 347-9593www.techrefinc.com
VHG Labs, Inc276 Abby RoadManchester, NH 03103(888) 622-7660www.vhglabs.com
Page 32
DXC 2009 – Preparation of Liquid Samples
July-20092009 DXC Liquid Preparation63
www.bruker-axs.com
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