Sensitivity Improvement of Odor Sensing System Using Ball SAW Devices

In this report, we improve a sensitivity of odor sensing system using ball SAW devices. Although, we reported the three-flavor identification using four ball SAW devices with different sensing films, the concentrations of the fruits flavors had to be high in the previous study. Thus several optimizations were performed here. First, we optimized the coating parameters of AC electrospray method. Second, we optimized sensing film thickness. Thirdly, we used Savitzky-Golay filter for smoothing response waveforms. After the improvement, we could detect butanol of 90ppb below human threshold. Finally we found that the response speed of ball SAW devices are superior to that of QCM with comparable sensitivity.