Detection of trinitrotoluene via deflagration on a microcantilever

Abstract

We describe in detail the detection of deflagration of trinitrotoluene (TNT) deposited on a piezoresistive microcantilever and point out its possible use for explosive-vapor detection. The deflagration of TNT causes the cantilever to bend (due to released heat) and its resonance frequency to shift (due to mass unloading). Explosive vapors provide unique responses that are absent for “interferences” such as water or alcohol vapors. The proposed sensor makes possible a sensitive, miniature explosives detection device that may be deployed in large numbers. The minimum amount of TNT detected on the cantilever depends on the cantilever dimensions and was ≈50 pg for the batch of cantilevers used.

Ultrasensitive mass sensing using mode localization in coupled microcantilevers

“…The added mass of the target analyte, which binds to cantilever coatings due to molecule specific interactions, is detected as a decrease in the cantilever resonance frequency. Vapors, 1,2 trinitrotoluene ͑TNT͒ deflagration, 3 and individual virus particles 4 have been detected using this transduction mechanism. The most sensitive microcantilever based mass detection experiments using the frequency shift approach have reported attogram level detection in ultrahigh vacuum environments [5][6][7] and femtogram level detection under ambient conditions.…”

Micro-differential thermal analysis detection of adsorbed explosive molecules using microfabricated bridges

“…As with TPD, our method can take advantage of a programmable heating rate to increase the device sensitivity to specific thermal characteristics of interest. Experiments with thermally induced deflagration of adsorbed explosives on microcantilevers 16,17 were able to differentiate energetic materials from nonenergetic materials, however, they were not able to differentiate between the individual explosives. In addition to identifying energetic material, the micro-differential thermal analysis ͑DTA͒ approach presented here allows the identification of different explosives.…”

The Xsense project: The application of an intelligent sensor array for high sensitivity handheld explosives detectors

“…Upon binding of the molecules, the cantilever bends and the bending is detected electrically as a change in the resistance of the integrated piezoresistor or optically as a deflection of a laser light hitting the apex of the cantilever. Sensitive and selective sensors can detect trace amounts of explosives in real-time, as demonstrated for example with PETN, RDX [4] and TNT [5]. Recently, polymer cantilevers fabricated at DTU Nanotech were used for the detection of the nerve gas model DMMP [6].…”