Confirmation of Solid Phase Extracted Post‐Blast Explosives Residues Analyzed Using Pulsed Split Injection GC/MS

Abstract A pulsed split injection method was developed for the improved detection of explosives using gas chromatography with mass spectrometric detection (GC/MS) with negative chemical ionization for 12 organic explosives (nitramines, nitrate esters, nitroalkanes, nitroaromatics) and electron ionization with selected ion monitoring for triacetone triperoxide (TATP). An order of magnitude increase in signal (average factor of 13) was observed for all organic explosives with the utilization of the pulsed split injection for samples processed by solid phase extraction (SPE). The method was successfully applied to post‐blast explosives residue processed by SPE and syringe filtration as a confirmatory technique following gas chromatography with electron capture detection (GC/ECD) screening. Compared to current methodologies previously reported, a decrease in the false screen rate (the number of compounds that passed the screening criteria, but not confirmed present) was achieved when employing this method. Processing of post‐blast explosives samples using SPE decreased the false screen rate from 60% to 34%, while using syringe filtration decreased the false screen rate from 73% to 51%.