Vacuum Collection of Gunpowder Residues From Clothing Worn by Shooting Suspects, and Their Analysis by GC/TEA, IMS, and GC/MS

• NCJ Number: 203113
• Journal: Journal of Forensic Sciences Volume: 48 Issue: 5 Dated: September 2003 Pages: 961-972
• Author(s): Arie Zeichner Ph.D.; Baruch Eldar; Baruch Glattstein M.Sc.; Avi Koffman B.Sc.; Tsippy Tamiri M.SC.; Dan Muller Ph.D.
• Date Published: September 2003
• Length: 12 pages
• Publication Format: Article
• Publication Type: Report (Study/Research)
• Language: English
• Country: United States of America

Annotation

This paper reports on experiments conducted to collect gunpowder (propellant) residues from shooters' clothing by vacuum and to analyze them by gas chromatography/thermal energy analyzer (GC/TEA), ion mobility spectrometry (IMS), and gas chromatography/mass spectrometry (GC/MS).

Abstract

The objective of the experiments was to assess the applicability of the portable vacuum sampler, the fiberglass, and the Teflon filter supplied with the commercial IMS instrument for the collection of propellant residues from clothing items and their subsequent analysis by GC/TEA, IMS, and GC/MS. Four solvents were assessed for the extraction of the residues from the filters. The samples were centrifuged and/or filtered, concentrated by evaporation, and analyzed without any additional clean-up steps. The IMS instrument consists of two main areas: the reaction region and the drift region. In the reaction region, the atmospheric pressure carrier gas (purified air), the reactant gas (hexachloroehtane), and an internal calibrant (4-nitrobenzonitrile) are ionized by a 63Ni beta emitter to form Cl ions. The reactant ions can then undergo one or more ion/molecule reactions with the analyzed material. The various ions migrate in the drift region, where an electric field gradient is applied and the ions are separated according to their mobility (drift time). The obtained mobility spectrum is called plasmagram. The plasmagrams were analyzed automatically by the programmed algorithm in the Barringer IMS. Study results indicate that it is feasible to use the IMS portable vacuum sampler to collect gunpowder residues from the clothing of suspected shooters after it has been sampled by the tape-lift method for primer residues. GC/TEA and IMS are sufficiently sensitive to detect and identify gunpowder residues in real-life samples. Formation of two peaks related to NG in the GC/TEA chromatograms increases the probability of its identification by this method. 1 table, 9 figures, and 23 references