Detection of the explosive nitroaromatic compound simulants with chemosensory systems based on quartz crystal microbalance and chemiresistive sensor arrays

The work is devoted to investigations of possibility of rapid detection and subsequent identification of explosive substances by using the arrays of two types of sensor elements: quartz crystal microbalances and chemiresistive electrodes. Thin layers of calixarene compounds and composites of electrically conductive polymers, respectively, were used as the sensitive coatings. Several types of nitroaromatic compounds from nitrotoluene series were chosen as simulants of explosive substances: O-Nitrotoluene (2-MNT) and Nitrobenzene (MNB), the concentration of these volatile compounds varied from 10 to 100 ppm. The observed detection threshold, depending on the type of analyzed explosive simulants, was within the range of 1 to 10 ppm for quartz crystal sensors with calixarene sensitive films, and the response time was within 10...20 s for quartz crystal sensors and up to 1 min for chemiresistive sensors. It has been shown that among the tested calixarenes there are samples with high selective sensitivity. The possibility of qualitative identification of explosives at relatively low concentrations by using the statistical methods of chemical patterns recognition (the so-called "electronic nose") has been demonstrated.