ISSN: 0022-1198
CODEN: JFSCA
Published Online: 17 August 2005
Page Count: 5

Analysis of Glass Fragments by Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry and Principal Component Analysis
Aeschliman, DB
Iowa State University (ISU), Iowa

Baldwin, DP
Iowa State University (ISU), Iowa

Saetveit, NJ
Iowa State University (ISU), Iowa

Houk, RS
Iowa State University (ISU), Iowa

Bajic, SJ
Iowa State University (ISU), Iowa

(Received 26 February 2005; accepted 26 April 2005)

Abstract

Laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) is used to differentiate glass samples with similar optical and physical properties based on trace elemental composition. Laser ablation increases the number of elements that can be used for differentiation by eliminating problems commonly associated with dissolution and contamination. In this study, standard residential window and tempered glass samples that could not be differentiated by refractive index or density were successfully differentiated by LA-ICP-MS. The primary analysis approach used is Principal Component Analysis (PCA) of the complete mass spectrum. PCA, a multivariate analysis technique, provides rapid analysis of samples without time-consuming pair-wise comparison of calibrated analyses or prior knowledge of the elements present in the samples. Probabilities for positive association of the individual samples are derived from PCA. Utilization of the Q-statistic with PCA allowed us to distinguish all samples within the set to a certainty greater than the 99% confidence interval.

Keywords:
forensic science, glass comparisons, elemental analysis, laser ablation-inductively coupled plasma-mass spectrometry, principal component analysis

Paper ID: JFS2005088
DOI: 10.1520/JFS2005088
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