The Work of the Explosives & Gunshot Residues Unit of the Forensic Science Service (UK)

Abstract

Explosives and gunshot residues trace analysis has been centralised in a purpose-built facility at the Birmingham Forensic Science Laboratory. A combined swabbing kit has been designed to recover

explosives and gunshot residues from skin surfaces and hair. Clothing is examined by vacuum filtration onto membrane filters. Samples are cleaned-up in a micro-column procedure. Most of the major components of explosives and ammunition propellants may be detected sensitively and with substantial specificity by high-performance liquid chromatography with amperometric detection at a mercury drop electrode. For confirmation of their identities the HPLC peaks are trapped out and examined by gas chromatography with a Thermoelectron TEA detector. Ammunition primer particles are detected by scanning electron microscopy with X-ray analysis. Examples of the application of the techniques in casework are presented.