SLIDE 1
The use of laser-ablation inductively coupled mass-spectrometry (LA-ICP-MS) in mineralogical and petrological studies
Zdzisław M. MIGASZEWSKI, Agnieszka GAŁUSZKA, Sabina DOŁĘGOWSKA Jan Kochanowski University in Kielce Institute of Chemistry Geochemistry and the Environment Div.
SLIDE 2 What is LA-ICP-MS?
Laser-ablation inductively coupled-mass spectrometry (LA- ICP-MS) is an analytical technique to determine trace elements at ppb levels in geologic and biologic solid microsamples. The mineral grains or plant tissues are viewed through a microscope and the sample surface is ablated with a fine pulsed laser beam. The laser shots create the sample aerosol which is swept directly into the inductively coupled argon plasma (ICP). Argon plasma at ~6000K (5727C) vaporizes sample and ionizes elements contained in sample aerosol. Mass Spectrometer separates and measures number of ions
- f an element at each mass generated by the ICP ion source.
SLIDE 3
Based on W.I. Ridley and F.E. Lichte (1998)
SLIDE 4
LA-ICP-MS ELAN DRC II, Perkin Elmer
SLIDE 5
LSX-500 CETAC laser ablation module [Nd:YAG (neodymium: yttrium-aluminum garnet) laser, 266 nm]
SLIDE 6
What are Laser Ablation System Capabilities?
In-situ trace element measurements directly from solids.
Microscale trace element mapping of polished thin sections or rough samples.
Rapid, multi-element determinations with sub-ppm limit of detection.
Minimal or no sample preparation required.
Spatial relationship or phase association characterized at high spatial resolution.
Qualitative to fully quantitative determinations.
Capable of <5% RSD precision.
SLIDE 7 Laser Ablation ICP-MS can be considered the trace element laser microprobe.
LA-ICP-MS is comparable to Electron Probe Microanalysis (EPMA) and Secondary Ion Mass Spectrometry (SIMS). Compared to EPMA and SIMS, LA-ICP-MS reveals less spatial resolution (lower magnification capabilities), but a few significant benefits:
no sample preparation; significantly improved trace element sensitivity; decreased matrix dependence; flexible sample ablation chamber for various
sample geometries.
SLIDE 8 Limitations (Achilles heel)
Laser ablation requires matrix matched reference
materials.
Differences in reporting results due to using different
lasers and standards.
Major developments for ICP-MS instrumentation do
not address specific needs of laser ablation.
The laser must produce particles of the exact
chemistry of the target sample (so no melting or fractionation).
The ICP-MS needs small droplets from the nebulizer,
so the laser has to produce small particles.
The laser must ablate the sample in the same way
as the calibration material.
SLIDE 9
Comparison with other techniques
Technique Strengths Weaknesses Comments
LA-ICP-MS
Rapid with no sample preparation, capable of sub- ppm detection, spatial information Lack of reference materials, matrix dependance, semi- destructive
Electron microprobe
High spatial resolution, non-destructive, surface analysis, easy to calibrate Sensitivity is limited below 100 ppm, interferences can be challenging
Ion microprobe
Sensitivity and spatial resolution, capable of isotopic analyses, Expensive and slow, matrix dependence
Bulk Analysis
Ultra-trace detection, well validated and accepted Time consuming and difficult preparation, no spatial information Validated and accepted for regulatory and legal situations Alan Koenig, Todor Todorov (2009)
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Petrographic study of a sample should be performed prior to LA analysis SEM and/or electron microprobe study need to be made for inclusion characterization and/or elemental zoning info
SLIDE 11 Stereoscopic image of the quartzite-quartz-pyrite breccia
- f the Podwiśniówka quarry (near Kielce, Holy Cross Mts)
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Pyrite grains within quartz matrix (transmitting light, crossed nicols)
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Pyrite grains within quartz matrix (reflected light, crossed nicols)
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20 µm
As-rich pyrite
SEM image of a pyrite grain
SLIDE 15
USGS Microanalytical Reference Materials (dr Steve Wilson): Glass BCR-2G, Basalt glass BHVO-2G, Basalt glass BIR-1G, Table Mountain Basalt Glass, Basalt Glass TB-1G, Synthetic basalt GSD-1G, Nephelinite Knippa Texas NKT- 1G, Carbonate MACS-3 and GPVI, Polymetal sulfide MASS-1; NIST 612 Glass
SLIDE 16
SLIDE 17 10 20 30 40 50 60 70 80 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ppb Rastering points Ce U
Single line raster
Striped chert from Ożarów (NE Holy Cross Mts, Poland)
SLIDE 18 500 1000 1500 2000 2500 3000 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 ppb Rastering points Ni Pb
Single line raster
SLIDE 19 Cu, Mn and Pb in silicified wood from Włoszczowice-Karsy (southern part of HCM)
Cu Mn Pb ppm 27 16 55 31 8 34 8 8 38
SLIDE 20
Quartz-quartzite-pyrite breccia of Podwiśniówka near Kielce (HCM)
1 10
SLIDE 21 Point Ag As Cd Co Cu Mo Ni Pb Zn ppm 1 0.14 37963 25 56 47 2 126 28 418 2 1.07 396 25 1 73 1 2 36 421 3 0.33 4929 25 18 49 33 2 420 4 1.08 379 25 1 73 1 2 37 422 5 0.47 6581 25 1 43 9 28 421 6 0.04 28386 25 17 48 1 66 25 422 7 2.20 50465 25 20 7 4 153 30 420 8 0.33 18271 25 19 52 82 30 421 9 1.30 82264 25 58 40 8 229 25 416 10 0.66 43353 25 33 29 4 159 20 420
Concentrations of selected elements in pyrite cement
- f quartz-quartzite breccia of Podwiśniówka
SLIDE 22 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 microns 1000 2000 3000 4000 5000 6000 7000 8000 9000 microns 200 ppm 300 ppm 400 ppm 500 ppm 600 ppm 700 ppm 800 ppm 900 ppm 1000 ppm
Ti
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 microns 1000 2000 3000 4000 5000 6000 7000 8000 9000 microns 1 ppm 2 ppm 3 ppm 4 ppm 5 ppm 6 ppm 7 ppm
Sm
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 microns 1000 2000 3000 4000 5000 6000 7000 8000 9000 microns 50 ppm 100 ppm 150 ppm 200 ppm 250 ppm 300 ppm 350 ppm
Yb
1000 2000 3000 4000 5000 6000 7000 8000 9000 10000 microns 1000 2000 3000 4000 5000 6000 7000 8000 9000 microns 20 30 40 50 60 70 80 90 100 110 120 130 140 150
Yb/Sm
Trace element maps of garnet
Courtesy of Alan Koenig
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