The Use of Capillary Electrophoresis in the Detection of Monomethylamine and Benzoate Ions in the Forensic Examination of Explosives Residues

Abstract

Capillary electrophoresis (CE) is used in the ATF Forensic Science Laboratories for the analysis of inorganic ions commonly encountered in post-blast residues including monomethylamine (MMA) and benzoate ions. Monomethylamine nitrate is found in Tovex®, a water gel explosive. Sodium benzoate is added to Pyrodex®, as a fuel and burn rate modifier. In the analysis of explosive residues, these ions are used as an indicator for the presence of Tovex® and Pyrodex®. Traditionally, these two ions, along with other ions of interest were analyzed by spot tests and ion chromatograph (IC). CE is currently being used in place of spot tests as a confirmation technique for IC.

Targeted and non-targeted forensic profiling of black powder substitutes and gunshot residue using gradient ion chromatography – high resolution mass spectrometry (IC-HRMS)

“…Benzoate was slightly more affected than nitrate and perchlorate, with both time since handling and hand washing. Amounts of chlorate, as expected, were significantly lower than the others immediately after handling (i.e., µg levels), but they slightly increased after 1 h after handling, which may indicate biodegradation of perchlorate to trace chlorate on hands [19,49]. After hand washing, concentration of chlorate lay below its LOQ.…”

“…In line with previous works [15], extracts of the original Pyrodex powder revealed high levels of benzoate, nitrate, chlorate and perchlorate (Table 2). These were likely due to the presence of sodium benzoate (burn rate modifier), potassium nitrate and potassium perchlorate (both oxidisers) in the formulation; presence of chlorate was explained through the degradation of perchlorate, which can occur with perchlorate-based black powder substitutes [19,49].…”

Direct detection of explosives on solid surfaces by low temperature plasma desorption mass spectrometry

“…Detection of explosives is of great analytical importance because of its application in forensic analysis, [1][2][3] public safety monitoring, 4,5 and environmental analysis. 6,7 As powerful instrumentation for structure elucidation, mass spectrometry (MS) plays an important role in the detection of explosives 3,[8][9][10] as it offers better sensitivity and specificity than any other common analytical technique.…”

Recent advances in the applications of CE to forensic sciences (2001–2004)

“…In 2001, Klapec and Ng [69] reported a capillary ion chromatographic method based on a commercial electrolyte (Waters IonSelect Low mobility cation electrolyte) and indirect UV detection at 214 nm for the analysis of monomethylamine (MMA) and benzoate ions contained in Tovex ® and Pyrodex ® explosives, respectively.…”