Chemical Sensing of Explosives in Water

The use of quartz crystal microbalance sensors coated with selected phthalocyanines having 2,2,3,3-tetra-fluoropropyloxy substituents as sensitive materials is proposed for the detection of different explosives in aqueous media, namely 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazinane (RDX), and C4 plastic explosive. In addition to the explosives, 2,4-dinitrotoluene, nitrobenzene and several other organic compounds were tested being concomitant chemicals of the explosive TNT or common water pollutants and thus possible interferents during chemical analysis of natural samples. The sensors were found to be very sensitive especially to TNT having detection limits in the range of 30-70 ppb in clean water as well as sea water. Sensors are working fully reversible and reliable over long periods of time suitable for repeated measurements of large sample quantities or continuous long-time monitoring of polluted areas.