Simultaneous electrochemical measurement of metal and organic propellant constituents of gunshot residues

Maika Vuki, Kwok Keung SHIU, Michal Galik, Aoife M. O'Mahony, Joseph Wang*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Citations (Scopus)

Abstract

The simultaneous electrochemical measurement of heavy-metal and organic propellants relevant to gunshot residues (GSRs) is demonstrated. Cyclic voltammetry (CV) and cyclic square-wave stripping voltammetry (C-SWV) are shown to detect, in a single run, common propellants, such as nitroglycerin (NG) and dinitrotoluene (DNT), along with the heavy metal constituents of GSR, antimony (Sb), lead (Pb), zinc (Zn) and barium (Ba). The voltammetric detection of the stabilizer diphenylamine (DPA) along with inorganic constituents has also been examined. The resulting electrochemical signatures combine - in a single voltammogram - the response for the various metals and organic species, based on the reduction and oxidation peaks of the constituents. Cyclic square-wave voltammetry at the glassy carbon electrode (GCE), involving an intermittent accumulation at the reversal potentials of -0.95 V (for Sb, Pb, DNT and NG) and -1.3 V (for Sb, Pb, Zn and DPA) is particularly useful to offer distinct electrochemical signatures for these constituents of GSR mixtures, compared to analogous cyclic voltammetric measurements. Simultaneous voltammetric measurements of barium (at thin-film Hg GCE) and DNT (at bare GCE) are also demonstrated in connection to intermittent accumulation at the reversal potential of -2.4 V. Such generation of unique, single-run, information-rich inorganic/organic electrochemical fingerprints holds considerable promise for 'on-the-spot' field identification of individuals firing a weapon, as desired for diverse forensic investigations.

Original languageEnglish
Pages (from-to)3265-3270
Number of pages6
JournalThe Analyst
Volume137
Issue number14
DOIs
Publication statusPublished - 21 Jul 2012

Scopus Subject Areas

  • Analytical Chemistry
  • Biochemistry
  • Environmental Chemistry
  • Spectroscopy
  • Electrochemistry

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