Determination of antimony in gunshot residues using GFAAS and SEM/EDX

Abstract

Transferring gunshot residue via adhesive tape is a very applicable technique for the collection of firearm discharge residue from the surface of hands and face. In this study, antimony was determined in 15 types of adhesive tape and the false positive possibility in the results was investigated. Adhesive tapes, which were provided by crime scene investigators and from a regional market, were analyzed with a graphite furnace atomic absorption spectrometer as used in Police Criminal Laboratories. In two samples, the measured antimony concentrations were 9.2 and 43.7 μg L-1, respectively, and high enough to cause false positives although most of the samples were clean. The source of antimony was detected via imaging and detailed elemental analysis of the samples. In addition, a simple method is proposed to prevent false positives. The method described is simpler, less costly, and faster than the modern approaches used for gunshot residue analysis and is based on the determination of antimony using GFAAS and SEM/EDX.