icp methods for consistent trace elemental data
DESCRIPTION
ICP Methods for Consistent Trace Elemental Data. WEALA Technical Workshop - 25-Apr-2013. The Analytical Process. Scope. Sampling. Sampling - Design. Bulk Prep. Particle Size Fractions for Metals Analysis. Aquatic Sediment (< 63 um). Terrestrial Soils (< 2 mm). - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/1.jpg)
ICP Methods for Consistent Trace Elemental Data
WEALA Technical Workshop - 25-Apr-2013
![Page 2: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/2.jpg)
The Analytical Process
Sampling
Bulk Prep
Analytical Prep
Analysis
Calculations and
Reporting
![Page 3: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/3.jpg)
Scope
WEALA• Focus on soil• Environmental slant (presenter’s bias)
“Consistency” relates to ‘variability’• Event-to-event consistency relies on
controlling systematic variability
![Page 4: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/4.jpg)
Sampling
“Sampling involves the selection from the total population of a subset of individuals upon which measurements will be made; the measurements made on this subset (or sample) will then be used to estimate the properties (or parameters) of the total population.”
Carter and Gregorich, pg. 1, first sentence
![Page 5: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/5.jpg)
Sampling - Design
• Total concentrations in the whole?• Extent and boundaries of a spill?
What question is to be answered?
• Account for heterogeneity/stratificationRepresentative of the site
• Precautions against contamination• Appropriate containers• Appropriate storage conditions and time
Protect sample integrity
Field sampling design and execution is the first consideration for consistency of data for a source or site
![Page 6: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/6.jpg)
Bulk Prep
Preparation of field samples for laboratory use and storage
Drying
Field moistAir dry (60°C)
Oven dry (105°C)
Sieving
< 6mm < 2mm
< 63 um
Splitting/Subsampling
Appropriate type of subsample;
Appropriate amount of subsample;Representative
subsample
Grinding
Break up clumps;Pulverize to defined
size
Archiving
As-received;Prepped
![Page 7: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/7.jpg)
Particle Size Fractionsfor Metals Analysis
Terrestrial Soils(< 2 mm)
Aquatic Sediment(< 63 um)
Particle size chart from Carter, 2008; Figure 55.1
![Page 8: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/8.jpg)
Analytical Prep
Extract/Dissolve Analytes from Solid Phase into Aqueous
Solution
Salinity Trace Metals
Special Techniques
![Page 9: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/9.jpg)
Salinity
• Defined in Carter, Handbook 60 and SSSA• Well-defined procedure:• Add water to saturation• Stand > 4 hr• Vacuum-filter
• Saturation % = 100 * Wwater / Wsoil• Analytical results conventionally reported as mg/L
Saturation Extract
• 1:1 or 1:5 most commonly listed • When unable to prepare a Saturation Extract (type
or amount of sample)• Report as mg/kg(?)
Other Extraction
Ratios
![Page 10: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/10.jpg)
Tessier Model -Metals Fractions in Sediments
• MgCl2, pH 7.0Exchangeable
• NaOAC/HOAc, pH 5.0Bound to Carbonates• NH2OH·H2O in 25% HOAc,
pH~2Bound to Fe-Mn Oxides
• H2O2/HNO3, pH~2 (+NH4OAc)Bound to Organic Matter
• HF and HClO4ResidualAnalytical Chemistry 51(7) June 1979
![Page 11: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/11.jpg)
Tessier Model – Extension to Terrestrial Soils(?)
• WaterSoluble
• MgCl2, pH 7.0Exchangeable
• NaOAC/HOAc, pH 5.0Bound to Carbonates• NH2OH·H2O in 25% HOAc,
pH~2Bound to Fe-Mn Oxides
• H2O2/HNO3, pH~2(+NH4OAc)Bound to Organic Matter
• HF and HClO4Residual
![Page 12: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/12.jpg)
Metals Fractionsof Environmental Significance
Soluble
Exchangeable
Bound to Carbonates
Bound to Fe-Mn Oxides
Bound to Organic Matter
Residual
‘Environmentally Available’
or‘Total Recoverable’
metals
![Page 13: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/13.jpg)
Standard Analytical Prep Procedures for Trace Metals
EPA 200.2 EPA 3050B ICPMS/GFAA
EPA 3050B ICPAES/FLAA
EPA 3050B* ICPAES/FLAA
Nominal Sample Mass (g - dry wt.) 1 1 1 1
1st Acid Addition
HNO3 Concentration 1 + 1 1 + 1 ConcHNO3 Volume (mL) 4 10 2.5HCl Concentration 1 + 4 Conc Conc
HCl Volume (mL) 10 10 10Temperature (°C) ~95 95 ± 5 95 ± 5 95 ± 51st Heating Time (min) 10 to 15 2nd Acid Addition
HNO3 Concentration Conc HNO3 Volume (mL) 5
Reflux Time (min) 30'heat and add acid until no change in
appearance'15 15
Evaporate to (mL) ~5
Peroxide Addition
30% H2O2 (mL) 3 DIW Volume (mL) 2
Additional 30% H2O2 1-mL increments until
minimal effervescence, to maximum 10 mL total
Evaporate to (mL) ~5
First Filter Treatment
Hot Conc HCl Rinse (mL) ≤ 5Hot DIW Rinse (mL) 20
Conc. HCl Digest Acid (mL) 5
Reflux Time (min) "until the filter paper dissolves"
Final Acid Addition
Condition "If a precipitate forms"
Conc. HCl (mL) 10Final Digest Volume (mL) 100 100 100 100Remove solids (if present) after or before Final Volume adjustment? after before before before
* EPA 3050B states "may be used to improve the solubilities and recoveries of antimony, barium, lead, and silver when necessary. These steps are optional and are not required on a routine basis"
![Page 14: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/14.jpg)
Applicable MetalsEPA 200.2 EPA 3050B
ICPMS/GFAAEPA 3050B
ICPAES/FLAAAluminum (Al) X XAntimony (Sb) X XArsenic (As) X X Boron (B) X Barium (Ba) X XBeryllium (Be) X X XCadmium (Cd) X X XCalcium (Ca) X XChromium (Cr) X X XCobalt (Co) X X XCopper (Cu) X XIron (Fe) X X XLead (Pb) X X XLithium (Li) X Magnesium (Mg) X XManganese (Mn) X XMercury (Hg) X Molybdenum (Mo) X X XNickel (Ni) X XPhosphorus (P) X Potassium (K) X XSelenium (Se) X X Silica (SiO2) Silver (Ag) X XSodium (Na) X XStrontium (Sr) X Thallium (Tl) X X XThorium (Th) X Tin (Sn) X Uranium (U) X Vanadium (V) X XZinc (Zn) X X
![Page 15: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/15.jpg)
Analytical Prep
Special Techniques
Hot-Water Extraction
Boron
Solvent Extraction
Sulphur
Fusion
Barite-Barium Silicon
![Page 16: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/16.jpg)
Analysis
• Multi-element• Wide dynamic range
• % to sub-ppt• Manageable interferences
Why ICP?
• ICP = Inductively-Coupled Plasma• For metals analysis, typically an argon plasma
sustained in a radio-frequency electromagnetic field• Serves to atomize and ionize the sample• Detection of the atoms/ions define the technique
(AES or OES; MS or CRC-MS; HR-MS)
What is
“ICP”?
![Page 17: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/17.jpg)
Anatomy of a Plasma
1Spectroscopy 16(6) June 2001
Plasma Formation1
Plasma Temperature Zones1
2Perkin-Elmer, 1997
Droplet Conversion in the ICP Source2
![Page 18: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/18.jpg)
Basic ICP Instrument Architecture
Perkin-Elmer, 1997
![Page 19: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/19.jpg)
Emission Spectroscopy
![Page 20: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/20.jpg)
Light Spectra
White Light (sunlight)
Emission Spectrum of Iron (Fe)
![Page 21: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/21.jpg)
Grating Equation
Palmer, C. and Loewen, E., Diffraction Grating Handbook, sixth edition; Newport Corporation, 2005.
mλ = d (sinα + sinβ), where m is the spectral order (an integer) and λ is the wavelength
![Page 22: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/22.jpg)
Rowland Circle Polychromator
Perkin-Elmer, 1997
![Page 23: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/23.jpg)
Spectral Overlap
Palmer, C. and Loewen, E., Diffraction Grating Handbook, sixth edition; Newport Corporation, 2005.
![Page 24: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/24.jpg)
Echelle Optical Mount
Perkin-Elmer, 1997
![Page 25: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/25.jpg)
2-D Spectral Array
Perkin-Elmer, 1997
![Page 26: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/26.jpg)
Atomic Mass Spectra
40 91.22
ZrZirconium
![Page 27: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/27.jpg)
Relative Abundance of the Natural Isotopes
Spectroscopy 17(10) October 2002; Perkin-Elmer
![Page 28: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/28.jpg)
Relative Abundance of the Natural Isotopes
Spectroscopy 17(10) October 2002; Perkin-Elmer
![Page 29: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/29.jpg)
Elements analyzed by ICPMS
http://www.perkinelmer.ca/EN-CA/CMSResources/Images/44-74849tch_icpmsthirtyminuteguide.pdf
![Page 30: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/30.jpg)
Plasma – Mass Spectrometer Interface
Spectroscopy 16(7) July 2001
![Page 31: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/31.jpg)
Quadrupole Spectrometer
Spectroscopy 16(10) October 2001
![Page 32: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/32.jpg)
Conventional ICPMS
Spectroscopy 17(2) February 2002 (edited graphic)
![Page 33: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/33.jpg)
Collision/Reaction Cell ICPMS
Spectroscopy 17(2) February 2002
![Page 34: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/34.jpg)
Collision/Reaction Cell ICPMS
Spectroscopy 17(2) February 2002
![Page 35: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/35.jpg)
Hi-Resolution ICPMS
Spectroscopy 16(11) November 2001
![Page 36: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/36.jpg)
Hi-Resolution ICPMS
Name Symbol MassAbundance
(%) Name Symbol MassAbundance
(%)
Oxygen 16O 15.994915 99.757 Iron 54Fe 53.939615 5.84517O 16.999132 0.038 56Fe 55.934942 91.75418O 17.99916 0.205 57Fe 56.93540 2.119
58Fe 57.93328 0.282Chlorine 35Cl 34.968853 75.78
37Cl 36.96590 24.22 Arsenic 75As 74.92160 100
Argon 36Ar 35.967546 0.336538Ar 37.962732 0.063240Ar 39.962383 99.6003
40Ar16O 55.957298 40Ar16O - 56Fe = 0.022356
40Ar35Cl 74.931236 40Ar35Cl - 75As = 0.009640
![Page 37: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/37.jpg)
Hi-Resolution ICPMS
Spectroscopy 16(11) November 2001
![Page 38: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/38.jpg)
Interferences in ICP
• Affects how much of the sample gets to the plasma or spectrometer
• Differences in viscosity, surface tension, TDS yield variations in solution transport and nebulization
Physical
• Affects the nature of the plasma or the analytes in the plasma
• Molecular compound formation; ionization; solute vaporization
Chemical
• Affects the intensity of the analyte signal reaching the detector
• Background shifts• Overlapping wavelengths/masses
Spectral
![Page 39: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/39.jpg)
Addressing Interferences
• Matrix-matching of standards with samples• Use of internal standard(s)• Water-saturated nebulization gas (prevent salt
build-up)• Dilution
Physical
• (Tend not to be prevalent in ICP owing to high energy)
• Optimization of operating conditions• Matrix-matching of standards with samples• Use of internal standard(s)• Dilution
Chemical
![Page 40: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/40.jpg)
Physical Effects in ICPMS -Space-Charge Interference
Spectroscopy 16(9) September 2001
![Page 41: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/41.jpg)
Addressing Interferences
Spectral – AES
• Matrix-matching• Off-peak correctionBackground
• Alternate wavelength• Inter-element correctionOverlap
![Page 42: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/42.jpg)
Correcting AES Spectral Interference
Off-peak background correction Inter-element correction
where,
determined previously from standards
http://inorganicventures.com/tech/icp-operations/spectral-interference-correction/correction-icp-oes
![Page 43: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/43.jpg)
Types of MS Spectral Overlap
• Two isotopes of same mass• e.g. 40Ar on 40CaIsobaric
• Molecular ions formed in the plasma• e.g. 40Ar35Cl on 75AsPolyatomic
• Mass discrimination based on m/z• e.g. 136Ba++ on 68Zn+
Double-charged
ions
![Page 44: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/44.jpg)
Addressing Interferences
Spectral – MS
• Matrix-matchingBackground
• Alternate mass• Mass equation• Collision/Reaction• Increase resolution
Overlap
![Page 45: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/45.jpg)
Correcting MS Spectral Interference
Alternate Mass Mass equation
where,
Spectroscopy 17(10) October 2002; Perkin-Elmer
![Page 46: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/46.jpg)
Correcting MS Spectral Interference
Collision/Reaction Increase Resolution
http://inorganicventures.com/tech/icp-operations/spectral-interference-correction/correction-icp-oes
![Page 47: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/47.jpg)
Calculation and Reporting
• Dilutions• Alternate lines• Correction equations
Method modifications
• mg/L to mg/kg (as required)Units
• As-received• Air-dried basis• Oven-dried basis
Moisture-basis
![Page 48: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/48.jpg)
Summary
The final result of an analytical measurement depends on a series of numerous decisions for processing the sample, each of which has an influence on the magnitude of that result
Consistency of results within or between sampling events depends on the consistency of the processes applied to the sample
ICP-based analytical techniques are valuable tools for measuring metals in soils but require understanding of their behaviour in the given sample matrix
![Page 49: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/49.jpg)
References• Boss, C.B. and Fredeen, K.J.; Concepts, Instrumentation and Techniques in
Inductively Coupled Plasma Optical Emission Spectrometry, Second Edition; The Perkin-Elmer Corporation, 1997.
• Carter, M.R. and Gregorich, E.G., eds., Soil Sampling and Methods of Analysis, Second Edition; Canadian Society of Soil Science, 2008.
• Palmer C. and Loewen, E., Diffraction Grating Handbook, sixth edition; Newport Corporation, 2005.
• Spectroscopy magazine and www.spectroscopyonline.com• Richards, L.A., ed., Agriculture Handbook No. 60: Diagnosis and
Improvement of Saline and Alkali Soils; USDA, 1954.• Tessier, A., Campbell, P.G.C., Bisson, B., Sequential Extraction Procedure for
the Speciation of Particulate Trace Metals; Analytical Chemistry: 15(7), June 1979, pp. 844-851.
![Page 50: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/50.jpg)
Questions
?
![Page 51: ICP Methods for Consistent Trace Elemental Data](https://reader037.vdocument.in/reader037/viewer/2022102801/568166f4550346895ddb524f/html5/thumbnails/51.jpg)