In situ detection of trinitrotoluene and other nitrated explosives in soils

The thermal decomposition of 2,4,6-trinitrotoluene (TNT), hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX), octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and other explosives over heated noble metal surfaces generates characteristic products that can be efficiently detected by amperometric gas sensors. This observation was exploited to develop a method for the selective in situ detection and quantitation of explosives contamination in soils. Amperometric sensing of the compounds generated from the thermal decomposition of soil-bound TNT was selective and sensitive over a broad range. Laboratory and field-usable probes that accommodate the electrochemical sensors, the thermal desorption/catalyzer unit or “heater”, and pneumatic components were designed, fabricated, and deployed. A field test demonstrated that this method is viable for in situ analysis of explosives.