Forensic analysis of a single particle of partially burnt gunpowder by solid phase micro-extraction–gas chromatography-nitrogen phosphorus detector

Solid phase micro-extraction (SPME) was adopted to extract organic gun shot residues (OGSRs) from a single particle of partially burnt gunpowder. The partially burnt particle samples were collected from gun shot residue (GSR) deposited near the target areas. OGSRs, such as diphenylamine (DPA), methyl centralite (MC), ethyl centralite (EC), from only one single particle of partially burnt gunpowder were successfully extracted by SPME and analyzed by a gas chromatography coupled to a nitrogen phosphorus detector (GC-NPD). The results confirmed that the new extraction procedure is capable of extracting trace amount of MC and EC as signature molecules for the identification of GSR. The method represents a solvent-free extraction as a complementary analytical procedure for the forensic analysis of GSR-related evidences. The new extraction scheme with the capability of analyzing single particle of partially burnt gunpowder can also be applied to the identification of explosive residues, such as in post-blast investigations of improvised explosive devices.