Detection of explosive compounds with the use of microcantilevers with nanoporous coatings

Real-time detection of nitroaromatic explosive compounds in various environments is a challenging task for forensics, antiterrorist activities, and global de-mining projects. The ability to detect trace levels of trinitrotoluene (TNT) in air and soil is a key measure in reducing fatalities from land mines among civilians and tracking explosive materials. In the present work we demonstrate that microcantilevers modified with a chemically responsive coating produce large (micrometer-scale) bending responses in the presence of vapor-phase TNT and its analogs, 1-mononitrotoluene (1-MNT) and 2,4-dinitrotoluene (2,4-DNT). Efficient delivery of low-vapor-pressure nitroaromatic analytes was achieved by heating the analyte delivery system and encasing the detector in a heatable flow cell. The magnitude of responses to TNT vapor increased and the response kinetics was dramatically accelerated as the detector temperature was raised from 22 degrees C to 40 degrees C. The noise-limited TNT detection threshold was estimated to be 520 ppt(v).