COMPARISON OF REFRACTIVE-INDEX, ENERGY DISPERSIVE-X-RAY FLUORESCENCE AND INDUCTIVELY COUPLED PLASMA ATOMIC EMISSION-SPECTROMETRY FOR FORENSIC CHARACTERIZATION OF SHEET GLASS FRAGMENTS

Fragments (in the milligram size range) from 81 tempered sheet glasses were used in order to evaluate the source discrimination capabilities of refractive indices (RI) and elemental composition, by using energy dispersive X-ray fluorescence (EDXRF) and inductively coupled plasma atomic emission spectrometry (ICP-AES). The X-ray intensities of five elements were determined by EDXRF with precisions of between 1 and 25%. The concentrations of nine elements were determined using ICP-AES and precisions of from less than 1 to about 10% were obtained. Both methods offer improved discrimination capability over RI measurements alone. The technique of EDXRF provides rapid, non-destructive testing and is widely available in forensic laboratories. The ICP-AES method offers the advantages of providing quantitative data on the concentration of elements, applicability to a greater number of elements and improved discrimination.