Elemental Analysis Of Glass & Paint Materials By Laser Ablation Inductively Coupled Plasma Mass Spectrometry (La-Icp-Ms) For Forensic Application

The elemental analysis of materials has become an important yet underutilized type of evidence at many crime scenes, including scenes of hit-and-run accidents. Although the utility of trace elemental analyses & comparisons for glass or paint fragments has been shown to offer a high degree of discrimination between different sources of these materials, the lack of method development, validation of methods & publication of the results in open literature have limited the adoption of this technology by the typical forensic laboratory. The proposed research has expanded on prior work (TSWG contract2002) to develop a solution analysis-based standard method for the elemental analysis of glass from a large number of sources & develop a database of data from the analysis of a large number of glasses. One significant disadvantage to solution analysis is the time consuming nature of the sample preparation, using acid digestion of the glasses for metal analysis. The methodology described within this report utilizes a laser ablation-sampling source prior to the ICP-MS analyte detection. A direct comparison of the results for solution & laser ablation analyses also provides additional data to pursue a more comprehensive study of the LA method development for glass comparisons. The results of the studies described within this report & the results of several groups yields excellent precision & low bias for the analysis of glass samples encountered in forensic casework. Glass sample size & sample heterogeneity/homogeneity considerations are also addressed.