Rapid and sensitive measurements of nitrate ester explosives using microchip electrophoresis with electrochemical detection

Abstract

This article describes an effective microchip protocol based on electrophoretic-separation and electrochemical detection for highly sensitive and rapid measurements of nitrate ester explosives, including ethylene glycol dinitrate (EGDN), pentaerythritol tetranitrate (PETN), propylene glycol dinitrate (PGDN) and glyceryl trinitrate (nitroglycerin, NG). Factors influencing the separation and detection processes were examined and optimized. Under the optimal separation conditions obtained using a 15 mM borate buffer (pH 9.2) containing 20 mM SDS, and applying a separation voltage of 1500 V, the four nitrate ester explosives were separated within less than 3 min. The glassy-carbon amperometric detector (operated at -0.9 V vs. Ag/AgCl) offers convenient cathodic detection down to the picogram level, with detection limits of 0.5 ppm and 0.3 ppm for PGDN and for NG, respectively, along with good repeatability (RSD of 1.8-2.3%; n = 6) and linearity (over the 10-60 ppm range). Such effective microchip operation offers great promise for field screening of nitrate ester explosives and for supporting various counter-terrorism surveillance activities.

Determination of hydrazines by chip electrophoresis with contactless conductivity detection

“…The corresponding micro total analysis system (mTAS) concept offers tremendous potential for obtaining environmental, bioanalytical, or forensic information in a faster, simpler, and cheaper way compared with traditional laboratory-based instrumentation. In particular, on-site determination increases the speed at which analytical information can be generated and enhances the reliability of analytical data by eliminating problems associated with sample transfer and storage [2][3][4][5]. In this context, the determination of hydrazine compounds (hy) (hydrazine (Hy), methylhydrazine (MH), symmetrical dimethylhydrazine (SDMH), and unsymmetrical dimethylhydrazine (UDMH)) in environmental samples is associated with special challenges.…”

HME powder detection using space sampling and electrochemical sensors

“…PETN is a solid which has lower reduction peak current than other nitroesters, since it has to decompose prior to reduction in aqueous solutions 8 . Most liquid nitroesters are blended with solid substances and can be sampled as a solid mixture.…”

Recent advances in capillary electrophoresis instrumentation for the analysis of explosives

“…5b). [40] However, this microchip was not tested in real postblast or pre-blast samples, which could be relevant for the implementation of this technology in an extended way and useful for studying the speed, sensitivity, efficiency, portability, cost and sample size compared to conventional CE. New patents have proposed the use of portable and simple devices, which could be considered as chemical sensors, to overcome fast analysis of explosives, for example, a mobile app electrophoresis analysis system that provides chemical information [43] Another example is the invention of a device for detecting the presence of a hazardous target molecule in a sample, such as biological agents, toxic chemicals, poisonous gases, narcotics or traces of explosive material or residues, and where an electrophoretic or dielectrophoretic field gradient between the sample and the substrate is required.…”