NCJ Number
203125
Journal
Journal of Forensic Sciences Volume: 48 Issue: 5 Dated: September 2003 Pages: 1101-1107
Date Published
September 2003
Length
7 pages
Annotation
The case study reported in this paper demonstrates the power of discrimination of inductively coupled plasma mass spectrometry (ICP-MS) as an analytical method for glass analysis.
Abstract
The case involved the breaking of a window in each of 15 vehicles in a parking lot in order to gain entry into the vehicles. A total of 15 known samples from the windows of the cars and 42 questioned glass fragments recovered from the suspect and the police vehicle where he was sitting were analyzed. Density comparisons separated 1 of the known samples into 3 samples, increasing the number of known samples from 15 to 17. The concentrations of 16 elements were measured for all but 3 of the samples by using an external calibration ICP-MS method with internal standardization. Color assessment (noninstrumental) separated the 17 known samples into 2 groups, and refractive index measurements resulted in 6 groups when the Emmons double variation method was used, and 10 groups resulted when the Glass Refractive Index Measurement 2 (GRIM2) system was used. Elemental analysis alone differentiated all of the known samples from each other and associated four of the known sample fragments with several of the questioned sample fragments. The informing power of elemental analysis by a sensitive technique such as ICP-MS, when used by itself, produces excellent evidence of association between glass fragments. ICP-MS is particularly useful for samples that do not permit the measurement of thickness, as is the case with most recovered glass fragments. Straightforward statistical analyses of the data generated were used to differentiate between fragments known to originate from different sources, as well as to associate the recovered fragments with some of the known fragments. 8 tables and 22 references