The study results show that LIBS, when used in conjunction with refractive index (RI), provides high (greater than 90 percent) discriminating power for several glass types, including beverage glass, automobile headlamp glass, and float glass from automobile side and rear windows. LIBS and RI exhibited a lower discriminating power for automobile side-mirror glass, which is commonly found in forensic casework. A subset of the side-mirror glass that exhibited a small variance in measured RI values, however, was highly discriminated (greater than 90 percent) by LIBS+ RI. A comparative assessment of LIBS and LA-ICP-MS for several common sets of glass samples found LA-ICP-MS to be a more highly discriminating analytical technique, although the analysis time is longer. Based on these findings, the researchers recommend that failure to discriminate questioned and known samples by LIBS or LIBS+RI constitutes ground for reanalysis with a more highly discriminating technique. The authors caution that this study did not address the use of the evolving dual pulse LIBS techniques, which may prove to be more highly discriminating for glass analysis. This report includes a short background review of forensic glass analysis, a brief introduction to LIBS, and a description of the data analysis methods used to determine the discriminating power of LIBS. 10 tables, 4 figures, 30 references, and appended list of scientific presentations resulting from this research along with sample statistical analysis
Downloads
Similar Publications
- Training police for procedural justice: An evaluation of officer attitudes, citizen attitudes, and police-citizen interactions
- Media Contact and Posttraumatic Stress in Employees of New York City Area Businesses after the September 11 Attacks
- Perceptions of School Climate Among Subgroups of Aggressive and Victimized Youth