Analysis of organic components of smokeless gunpowders: High‐performance liquid chromatogaphyvs.micellar electrokinetic capillary chromatography

Abstract

The aim of the present study was to verify the analytical performances of high-performance liquid chromatography (HPLC) and micellar electrokinetic capillary chromatography (MEKC) for the separation and qualitative determination of a selected group of organic components of smokeless gunpowders. The HPLC method was based on a gradient reversed-phase elution with a mobile phase composed of 0.17 M H(3)PO(4)/methanol; detection was performed by UV absorption at the wavelengths of 220, 254, and 270 nm. The MEKC experiments were carried out by using uncoated fused-silica capillaries (50 microm inside diameter, 50 cm effective length) and a running buffer composed of 10 mM sodium tetraborate at pH 9.24 added with 25 mM sodium dodecyl sulfate (SDS); the applied voltage was 25 kV; detection was either at a fixed wavelength UV of 214 nm or with a diode-array detector operating in the wavelength range from 190 to 350 nm. Both reversed-phase HPLC and MEKC techniques succeeded in resolving the tested standard mixtures of organic components of smokeless powders. Although the sequence of elution of the different analytes was slightly different between HPLC and MEKC, a statistical analysis based on the Spearman's rank correlation test showed that the two separation patterns were highly correlated. HPLC and MEKC were comparable in terms of elution/migration time precision, whereas MEKC showed higher reproducibility of peak areas. The interfacing of capillary electrophoresis with diode array UV detection provided distinct UV spectra of the individual analytes, thus improving, on the detection side, the analytical selectivity and identification power of capillary electrophoresis.

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

“…This is conceivable both being based on hydrophobic interactions between the stationary or pseudostationary phase and the analytes. The use of diode array UV detection for recording peak spectra proved to be more feasible with CE in comparison to gradient HPLC, because of the lack of gradient-related drift of the detector signal occurring in the latter technique [65].…”

A Method for the Differentiation of Single-Base and Double-Base Smokeless Powders using the Hanging Drop Technique

“…Smokeless powders are traditionally analyzed in a laboratory setting and require timeconsuming protocols and expensive confirmatory instrumentation. Previous studies cite the use of gas chromatography-mass spectrometry (GC-MS), high performance liquid chromatography (HPLC), ion chromatography, and micellar electrokinetic capillary electrophoresis [5][6][7][8][9][10]. Though the confirmatory result is advantageous, the potential drawbacks for many laboratories are a drain on the economic and time resources.…”

Recent trends in organic gunshot residue analysis

“…Stirring, however, was considered to be ineffective by Zeichner and Eldar, who reported that sonication is imperative to achieving an efficient extraction [38]. This is generally followed by centrifugation, which allows for the collection of the supernatant and filtration [8,14,46]. Alternatively, the sample may be concentrated prior to centrifugation by blowing it to near dryness [38], or complete dryness [10][11][12].…”

“…The majority of these studies have been reported since 2010 [2,[7][8][9][10][11][12]. A few studies, including one review [3], prior to 2010 have been included for the purpose of comparison [13][14][15]. This has resulted in a list containing 136 organic compounds that could be associated with smokeless powders and gunshot residue.…”

“…Solvent extraction involves dissolving the sample by submerging the powder or object containing the OGSR sample in a solvent for a period of time. Dissolving the sample may be done in an aqueous solution [38,46] or in organic solvents, such as methanol [8,12,14], methylene chloride [10,11,45], acetonitrile [10] or methyl ethyl ketone [54]. This process can be aided and thus accelerated, by stirring or (ultra)sonication [8,14,46].…”