Trace Detection of 2, 4, 6-Trinitrotoluene Using Electrochemical Gas Sensors

In this article, selective and sensitive detection of trace amounts of 2, 4, 6-trinitrotoluene (TNT) is demonstrated. The screening system is based on a sampling/concentrator front end and electrochemical potentiometric gas sensors as the detector. Preferential hydrocarbon and nitrogen oxide(s) mixed potential sensors with integrated heaters were used to capture the signature of the explosive. Quantitative measurements based on hydrocarbon and nitrogen oxide sensor responses indicated that the detector sensitivity scaled proportionally with the mass of the explosives (down to 250 ng). The sensitivity was found to depend on the flow rate and sensor orientation. The sensitivity was found to increase with increasing flow rate. This detection technique has the potential to become an orthogonal technique to the existing explosive screening technologies for reducing the number of false positives/false negatives in a cost-effective manner.