Separation and identification of anions using porous graphitic carbon and electrospray ionization mass spectrometry: Application to inorganic explosives and their post blast residues

Abstract

Identification of the anions in inorganic explosives and their post-blast residues using ion chromatography (IC) and/or capillary electrophoresis (CE) is well established. However, IC and CE instrumentation are not as common in forensic science laboratories. Furthermore, coupling IC and CE to a mass spectrometer can be challenging as volatile buffers are required or ion suppressors must be used. Porous Graphitic Carbon (PGC) is a relatively new stationary phase type that is available for High Performance Liquid Chromatography (HPLC). PGC is known for its high retention of polar species and separation of anions using PGC has been demonstrated. In this work, a PGC (2.1 Â 100 mm) column was coupled to an electrospray ionization mass spectrometer (ESI-MS) for the analysis and detection of anions. Several parameters of the method were optimized including ion source temperature (550 C), MS cone voltage (75 V), injection volume (1 mL), solvent composition (1% formic acid in water), and column temperature (80 C). This resulted in a method that separated 6 anions Cl À , NO 3, and dicyandiamide (DCDA) in less than 5 min. Several low explosive powders were analyzed intact and after burning. Finally, the post-blast residues of two black powder substitutes were extracted from pipe bomb container fragments and analyzed using this technique.

Analytical methodologies using carbon substrates developed by pyrolysis

“…In general, the interaction of glassy carbon substrates with analytes is determined by a combination of hydrophobic and electrostatic forces as well as their potential to interact via p-p stacking. 164 In order to preconcentrate pesticides, lms of polydopamine were prepared and in alkaline media over stainlesssteel bers. These bers provided a simple way to obtain enrichment factors in the 102-757 range.…”

Probing gunshot residue, sweat and latent human fingerprints with capillary-scale ion chromatography and suppressed conductivity detection

“…4,5 Many difficulties associated with capillary IC have only been addressed very recently to the extent where commercially available systems could be marketed. Some of these challenges lay in the provision of stationary phases with sufficient capacity and efficiency for small ion separations; [6][7][8] the development of capillary suppressor technologies for use with conductivity detection; 2,9,10 and the development of suitable IC detection modes which can operate sensitively at the micro-scale level. [11][12][13][14] Furthermore, the use of capillary zone electrophoresis (CZE) has long dominated capillary-scale separations of small ions by comparison and has shown to be particularly useful in forensic applications especially for samples of limited size.…”

Evaluation of selected buffers for simultaneous determination of ionic and acidic pesticides including glyphosate using anion exchange chromatography with mass spectrometric detection

“…Volatile eluents have been applied in chromatography using porous graphitic carbon, which has been shown to retain ionic analytes . Also, porous graphitic carbon columns have been coated permanently with ion‐pairing reagens to improve retention of anions .…”