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A Comparison of Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) Micro X-Ray Fluorescence (uXRF) and Laser Induced Breakdown Spectroscopy (LIBS) for the Discrimination of Automotive Glass

NCJ Number
Benjamin Naes; Sayuri Umpierrez; Scott Ryland; Cleon Barnett; Jose R. Almirall
Date Published
October 2008
6 pages
This article reports on a research project that compared laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), micro X-ray fluorescence spectroscopy (XRF), and laser induced breakdown spectroscopy (LIBS) for their discrimination power in analyzing a glass sample set that consisted of 41 fragments.
The comparison produced excellent discrimination results (>99 percent discrimination) with each of the methods. In addition, all three analytical methods produced similar discrimination results in terms of the number of pairs found to be indistinguishable. The small number of indistinguishable pairs that were identified all originated from the same vehicle. The results also show a strong correlation between the data generated from the use of µXRF and LA-ICP-MS, when comparing µXRF strontium intensities to LA-ICP-MS strontium concentrations. A 266 nm laser was utilized for all LIBS analyses, which provided excellent precision (< 10 percent RSD for all elements and < 10 percent RSD for all ratios, N - 5). The project also conducted a data analysis review for forensic glass examinations by LIBS and suggests several element ratios that provide accurate discrimination results related to the LIBS system used for this study. Different combinations of 10 ratios were used for discrimination, all of which assisted with eliminating Type I errors (false exclusions) and reducing Type II errors (false inclusions). The results demonstrate that the LIBS experimental setup described, when combined with a comprehensive data analysis protocol, provides comparable discrimination when compared to LA-ICP-MS and XRF for the application of forensic glass examinations. Given the many advantages of LIBS, most notably reduced complexity and reduced cost of the instrumentation, LIBS is a viable alternative to LA-ICP-MS and XRF for use in the forensic laboratory. (publisher abstract modified)

Date Published: October 1, 2008