Since the development of odor sensing system is required in many fields, we have been developing the system using QCM (Quartz Crystal Microbalance, 10 MHz AT-cut) array and neural-network pattern recognition. Since it is important to obtain stable sensor responses, a sensing film of lipid blended with PVC (polyvinyl chloride) was studied here. First, we studied the stability of various sensing films e. g. , phospholipids, GC liquid stationary phase materials and others in odor sensing system. It was found that most of lipids were stable, while PEG 200, octadecane and DBP were not stable materials. Second, we studied to obtain a stable QCM sensor using a sensing film blended with PVC. 4 plasticizers blended with PVC were systematically characterized, analyzing the pattern of QCM sensor responses by multivariate analysis. It was found that the pattern of DOPP was very different from that of PVC. Thus, we adopted DOPP as plasticizer and the stable sensor response was obtained using a lipid film blended with both PVC and DOPP. Finally, we studied the influence of sensing film materials on the stability of QCM sensors. It was found that the loss of sensing film mass after many vapor exposures depended upon the molecular weight.

Since odor sensing system is required in many fields, we have developed the system using QCM (Quartz Crystal Microbalance) sensor array and neural-network pattern recognition. In the present study, the mixed sensing films of two kinds of liquid-phase materials were characterized. As a result, it was found that the variety of sensing films were obtained by mixing two kinds of liquid-phase materials. The relative remnant of sensing film after repeated exposures was examined, and mixed films of two kinds of liquid-phase materials were found stable for the sensing materials.