Detection of four alcohol homologue gases by ZnO gas sensor in dynamic interval temperature modulation mode

Metal oxide semiconductor (MOS) gas sensors have poor selectivity, especially in volatile organic compounds (VOCs). Dynamic measurement method of gas sensors can bring a potential to resolve this problem. However, it is also a challenge to distinguish homologue gases with the same functional group. In this paper, four alcohol homologue gases were detected by a ZnO gas sensor. The period of triangular wave is changed to explore the optimal temperature range in dynamic interval temperature modulation mode for detecting ethyl alcohol, n-propyl alcohol, isopropyl alcohol and n-butyl alcohol. The experimental results show that only when the low temperature is lower than 180 °C and the high temperature is higher than 460 °C, the unsaturation phenomenon can be solved, so as to realize the qualitative and quantitative analysis of the four alcohol homologue gases. Under this experimental condition, the concentration gradient measurement of 100–400 ppm is carried out. After the optimization with the decision tree classification algorithm, the recognition accuracy of the four alcohol homologue gases is 97.62%.