Detection of chemical warfare agents using nanostructured metal oxide sensors

The feasibility of thick-film chemical sensors based on various semiconductor metal oxides to reliably detect chemical warfare agents has been studied. Nanocrystalline semiconductor metal oxide (SMO) powders were used as initial materials for the sensors’ fabrication. The thick films were prepared using a simple drop-coating technique accompanied with in situ annealing of the deposited films by a heater that is integrated into the sensor's platform. The sensors were exposed to mixtures of hexane, diesel oil vapor, methanol, 1,5-dichloropentane (DCP), or dimethyl methylphosphonate (DMMP) with air. DCP and DMMP were considered as simulants of mustard gas and nerve agents respectively. The performance of the sensors was investigated over a wide range of operating temperatures. They were additionally tested with mustard gas, sarin and soman at a certified live agent facility. The data obtained from the simulant and live agent testing are presented and discussed. In particular, attention is focused on the ability of an array of sensors to detect and identify agents in mixtures of interferents.