Electrochemical detection of nitromethane vapors combined with a solubilization device

• Nitromethane is a common product which can be used to make an explosive device.
• Electrochemical method was evaluated for NM detection in aqueous solution.
• Coupling a solubilization device and electrochemistry for the detection of vapors.
• Good efficiency of the system : less than 1 min to detect 8 ppmv in air.
• Detection efficiency demonstrated in room-measurement configuration.

During the past decade, the number of terrorism acts has increased and the need for efficient explosive detectors has become an urgent worldwide necessity. A prototype, Nebulex™, was recently developed in our laboratory. Basically, it couples the solubilization of an analyte from the atmosphere by a nebulization process and in-situ detection. This article presents the development and integration of an electrochemical sensor for the detection of nitromethane, a common chemical product that can be used to make an improvised explosive device. A gold screen-printed electrode was used in a flow-cell and a detection limit of 4.5 µM was achieved by square wave voltammetry. The detection method was also determined to be selective toward nitromethane over a large panel of interfering compounds. Detection tests with the Nebulex™ were thus carried out using a custom-made calibrated nitromethane vapor generator. Detection times of less than one minute were obtained for nitromethane contents of 8 and 90 ppmv. Further measurements were performed in a room-measurement configuration leading to detection times in the range of 1–2 min, clearly demonstrating the system׳s efficiency under quasi-real conditions.

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