Method Development Using Laser Ablation And Solution Icpms And Their Application In Environmental Science And Forensic Provenance Studies
Inductively coupled plasma mass spectrometry (ICPMS) is an analytical technique that can be used to determine multiple elements and isotope ratios in a wide variety of samples. In this work, four projects are described that involve the method development using laser ablation (LA) and solution-based ICPMS and their application in environmental science and forensic (provenance) investigations. In the first project, plutonium (Pu) concentrations and 240Pu/ 239Pu atom ratios were measured in kelp, lichen, aquatic moss, and horse mussel collected on or near Amchitka Island, a former nuclear test in Alaska, and at a background site. The Pu in terrestrial and freshwater species had 240Pu/239Pu ratio signatures typical of northern hemisphere atmospheric fallout, whereas Pu ratios in marine species were elevated, which is characteristic of the northern Pacific Ocean. Potential sources of Pu to the marine species were identified, with high-yield tests conducted in the Marshall Islands being the most likely of these sources. The second project used LA-ICPMS for sourcing iron-rich pigments used in ancient pictographs in the Pecos River Archeological Region. Potential pigment materials (siltstone, ochre, quartzite, and rhyolite) were analyzed for elemental signatures and were compared to rock paint using multivariate statistics. Siltstone was identified as the most probable raw material used in the production of the paint. A pigment cake from near cave site 41VV74 was determined to have similar elemental patterns to siltstone. The third project studied the effect of glyphosate herbicide on the mineral levels in glyphosate-resistent (GR) soybeans. Results from both greenhouse and field studies shono statistical difference in mineral concentrations between glyphosate-treated soybean and the control. This work supports the claim that application of glyphosate should have no significant impact on mineral concentrations in GR soybeans. In the fourth project, a new analytical method using LA-ICPMS was developed for the rapid determination of select dietary minerals and trace elements in commercial herbal supplement capsules. The analytical results were comparable to that using conventional solution-nebulization ICPMS. Chemometrics was successfully applied to discriminate the different manufacturers of the same herbal supplements according to the chemical signatures.
Glyphosate Herbicide, Herbal Supplement, Icpms, Plutonium, Rock Paint, Chemistry
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