title: Assessment and forensic application of laser-induced breakdown spectroscopy (LIBS) for the discrimination of Australian window glass.
abstract: A commercially available laser-induced breakdown spectroscopy (LIBS) instrument was evaluated for the determination of elemental composition of twenty Australian window glass samples, consisting of 14 laminated samples and 6 non-laminated samples (or not otherwise specified) collected from broken windows at crime scenes. In this study, the LIBS figures of merit were assessed in terms of accuracy, limits of detection and precision using three standard reference materials (NIST 610, 612, and 1831). The discrimination potential of LIBS was compared to that obtained using laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), X-ray microfluorescence spectroscopy (μXRF) and scanning electron microscopy energy dispersive X-ray spectrometry (SEM-EDX) for the analysis of architectural window glass samples collected from crime scenes in the Canberra region, Australia. Pairwise comparisons were performed using a three-sigma rule, two-way ANOVA and Tukey's HSD test at 95% confidence limit in order to investigate the discrimination power for window glass analysis. The results show that the elemental analysis of glass by LIBS provides a discrimination power greater than 97% (>98% when combined with refractive index data), which was comparable to the discrimination powers obtained by LA-ICP-MS and μXRF. These results indicate that LIBS is a feasible alternative to the more expensive LA-ICP-MS and μXRF options for the routine forensic analysis of window glass samples.
authors.affiliation: National Centre for Forensic Studies, University of Canberra, Canberra, ACT 2601, Australia. Electronic address: moteaa.el-deftar@canberra.edu.au.
authors.forename: Moteaa M
authors.initials: MM
authors.lastname: El-Deftar
authors.affiliation: Forensics, Australian Federal Police, GPO Box 401, Canberra, ACT 2601, Australia. Electronic address: naomi.speers@afp.gov.au.
authors.forename: Naomi
authors.initials: N
authors.lastname: Speers
authors.affiliation: Research School of Earth Sciences, Australian National University, Canberra, ACT 0200, Australia. Electronic address: stephen.eggins@anu.edu.au.
authors.forename: Stephen
authors.initials: S
authors.lastname: Eggins
authors.affiliation: Ecochemistry Laboratory, Institute for Applied Ecology, University of Canberra, Canberra, ACT 2601, Australia. Electronic address: simon.foster@canberra.edu.au.
authors.forename: Simon
authors.initials: S
authors.lastname: Foster
authors.affiliation: National Centre for Forensic Studies, University of Canberra, Canberra, ACT 2601, Australia. Electronic address: james.robertson@canberra.edu.au.
authors.forename: James
authors.initials: J
authors.lastname: Robertson
authors.affiliation: National Centre for Forensic Studies, University of Canberra, Canberra, ACT 2601, Australia. Electronic address: chris.lennard@canberra.edu.au.
authors.forename: Chris
authors.initials: C
authors.lastname: Lennard
keywords: Forensic glass analysis; LA-ICP-MS; LIBS; SEM-EDX; μXRF