Determining the Lifetime of Detectable Amounts of Gunshot Residue on the Hands of a Shooter Using Laser-Induced Breakdown Spectroscopy
Chemistry and Biochemistry
Laser-induced breakdown spectroscopy (LIBS) has been used to determine the period of time that a shooter will test positive for gunshot residue (GSR) after firing a revolver. Multiple rounds of primer were fired and samples collected at multiple hour intervals using an adhesive tape pressed against the skin. Samples were analyzed directly using a commercially available laser-induced breakdown spectrometer where barium emission (originating from barium nitrate in the primer) was observed. Population statistics were used to compare suspected GSR to a library of blank samples from which a threshold value was established. Statistically significant results, positive for GSR, are obtained 5.27 days after a firearm discharge using these techniques.
Rosenberg MB and Dockery CR. 1 November 2008. Determining the lifetime of detectable amounts of gunshot residue on the hands of a shooter using laser-induced breakdown spectroscopy. Appl Spectrosc 62:1238,1241(4).