A wireless electrode-free QCM-D in a multi-resonance mode for volatile organic compounds discrimination

Wireless sensor technology is a facile way of realizing low cost and miniaturized device for the detection of the volatile organic compounds (VOCs). A wireless electrodeless quartz crystal microbalance with dissipation (WE-QCM-D) sensor array was developed by using a single sensor working in a multi-resonance mode, which obtained an acoustic spectra of the quartz crystal at four harmonics (6 MHz, 18 MHz, 30 MHz and 42 MHz). Multi-responses (frequency shift, and energy dissipation) of WE-QCM-D sensor array were obtained via a ring-down mode and employed as discrimination factors for VOCs. The gas discrimination capability of the WE-QCM-D sensor array has been tested by coating a 100 μ g polyvinylpyrrolidone film on the quartz disc and achieved an optimal recognition rate of 97.5 % with K nearest neighbor algorithm. The results indicate that the single element WE-QCM-D sensor array could be a promising way to realize compact and low-cost VOCs monitoring systems.