Zeolite-modified cantilevers for the sensing of nitrotoluene vapors

Zeolite-coated cantilevers have been developed and used for the detection of different gases, and, in particular, of nitrotoluene, as an example of an explosive-related molecule. Different cantilever designs (rectangular or paddle-shaped) and different methods of zeolite deposition have been investigated. For nitrotoluene detection, Co-exchanged BEA (Co-BEA) zeolites have been prepared, and deposited on cantilevers by a microdropping method. The exchange with Co increased the affinity of the sensor towards nitrotoluene, and as a consequence Co-BEA coated cantilevers were able to detect nitrotoluene gas phase concentrations below 1 ppmV, while maintaining a significantly lower sensitivity towards other gas phase species.