Examination of Firearms Review: 2007 to 2010 - Interpol

Scherperel et al. (150) show a method for extraction and characterisation of
smokeless powder additives (methylcentralite (MC), EC and DPA) using tandem
mass spectrometry (nESI-MS), without the use of chromatographic separation
methods. From seven types of gun powder in unburned form, only two could not
be distinguished based on physical appearance of the unburned grain, solubility
in methanol and the nESI-MS technique. Samples from the burned powder were
used to successfully identify low levels of EC using Collision-Induced
Dissociation (CID)-MS/MS. The authors conclude that nESI-MS has great
potential for application in GSR analysis.
Zhao et al. (151) demonstrate the applicability of Desorption ElectroSpray
Ionisation (DESI)-MS/MS spectrometry, applied directly on the surface to be
sampled, for the detection of stabilizers (MC, EC, DPA). The DESI sampler can
even be applied directly on the human skin and the analysis carried out using a
portable MS/MS - making this potentially a field-operation technique.
Contamination of the surface by milk, soft drinks and dust does not influence the
measurements. Other surfaces were also tested, such as glass, rubber and
leather gloves, towel, cotton and hair. As far as sensitivity and persistence are
concerned, MC could still reliably be detected for up to 12 h after the shooting,
and it could still be detected after 6 hand washings.
3.4 Book review
Adlard (152) in a review of a book by Wallace “Chemical Analysis of Firearms,
Ammunition and Gunshot Residue”, describes the collective knowledge and
experience gathered by the scientists at the Northern Ireland Forensic Science
laboratory. The book compiles the results obtained using the diverse instruments
available for the analysis of GSR and, to a lesser extent, explosives.
36