Feasibility of an accelerated PVAL method for the collection of GSR and biological traces.

The polyvinyl alcohol method (PVAL) is known as an effective technique to thoroughly collect traces of gunshot residue (GSR) from different surfaces, e.g., from hands or gunshot wounds. Despite obvious advantages over other methods using adhesive tapes, PVAL is still not widely accepted and applied in routine case work due to a required acquisition time of at least 15 to 20 min for a single shooting hand. In this study, the feasibility of a modified procedure taking 6 to 8 min per sample is tested within the frame of an experimental setting including (1) the collection of GSR from experimental gunshots with a semi-automatic pistol and lead-containing primer ammunition and (2) a simple experimental setting involving dry and moist artificial blood traces. In a third step, samples of four gun-associated suicide cases and one attempted suicide case were taken and analyzed. Furthermore, an exemplary implementation into a work flow of modern instrumental techniques of GSR analysis is presented.