Response Differences of Binary Vapors from Mixtures in Liquid and Gas Phases

Response differences in binary mixture vapors are investigated by using two systems including the liquid phase and gas phase mixing systems. The response signal with various mixing ratios are analyzed for methanol-acetone and ethanol-acetone mixtures in both maximum response and decay characteristic during exposed and recovery periods. Both feature characteristics can be extracted by discrete wavelet transform. The classification patterns of binary mixing vapors are identifying by principal component analysis. The results show that the mixture points at various ratios are clearly separated and located far from to the pure acetone vapor point. The relative high vapor pressure of acetone plays significant role on separation effect and also on the different response in liquid and gas phase mixing systems. The main feature of these response differences in binary vapors from mixtures in liquid and gas phase can be extracted from the decay characteristic of these various sensor responses.