A wireless-electrodeless quartz crystal microbalance with dissipation DMMP sensor

Highly sensitive chemical warfare agents (CWAs) detection is demanded against the usage of the CWAs for war or terrorism aims. A dimethyl methylphosphonate (DMMP), simulant for sarin, monitoring sensor based on a homemade wireless-electrodeless quartz crystal microbalance with dissipation (QCM-D) was developed. With this noncontact configuration, deterioration of the sensing ability cause by the electrodes and drilling on the gas chamber for wire lead was avoided. Nano-structured hollow ball-like indium oxide (In2O3) was synthesized using a facile hydrothermal method and then decorated with cubic gold particles (In2O3-Au). Both of them were applied as the sensing films to detect DMMP. The In2O3-Au based QCM-D sensor exhibited 2.1 Hz/ppm to DMMP range from 5 ppm to 50 ppm, which was 400% higher compared to the undecorated one. Moreover, with the simultaneously monitored dissipation value, desorption processes of DMMP was further investigated and the overshoot that appear in some researches was explained in terms of visco-elastic variations in mechanical stiffness. The results suggest that the wireless-electrodeless QCM-D could be a promising strategy for observation of materials under dynamic conditions.