Detection and identification of the gas mixtures of n-propyl alcohol and iso-propyl alcohol based on ZnO sensor under dynamic temperature modulation

N-propyl alcohol and isopropyl alcohol are common raw materials and solvents used in cosmetic manufacturing processes, and they can pose a health risk to production workers. Rapid online detection of their concentrations can provide protection for workers' health. However, the detection of the same type of gases with the same functional groups, especially the mixture of gases, is still a great challenge. In this paper, a simple method for detecting the concentration of a single gas in a mixture of gases is proposed. A mixture of n-propyl alcohol and isopropyl alcohol was detected by the dynamic temperature modulation method, and the low temperature steady state response and the high temperature steady state response of the dynamic response curve were used to reflect the concentrations of n-propyl alcohol and isopropyl alcohol, respectively. The test data were processed and clustered using linear discriminant analysis and the different concentration combinations of the gas mixtures were successfully separated. The concentrations of n-propyl alcohol and isopropyl alcohol were fitted separately using linear fitting with R2 of 0.99867 and 0.98783, respectively. After the gas response mechanism was analyzed, acetone which is the oxidized transition product of isopropyl alcohol was selected and the gas responses of the mixtures of n-propyl alcohol and acetone, and ethyl alcohol and acetone were measured, which verified the feasibility of the method. This paper realizes the detection of gas mixtures of the same type, simplifies the concentration identification process, and lays the foundation for online rapid detection in production environments.