Cross effect of isopropanol and ethanol vapor on the response of a semiconductor gas sensor

The temperature dependencies of the response of Cu:SnO2 films to ethanol, 2-propanol vapours, as well as ethanol with 3% vol. background impurities of 2-prophanol in the working temperature range of 250-375°C. The aim of the study was to determine the effect of the 2-propanol background impurities on the sensor response to ethanol, as well as to assess the possibility of distinguishing a steam-air mixture containing pure ethanol vapors from a gas mixture of ethanol/2-propanole by means of single-sensor signal statistical processing. The temperature dependencies analysis of the sensor response showed that the temperature at which the maximum response is observed is individual for each substance. A selective response to substances was detected. It was found that the 3% vol. isopropyl alcohol compound decreases the response to ethanol in the tested concentration and temperature range. Statistical processing of experimental data by the principal component analysis (PCA) and cross-validation of the model by the ellipsoid and nearest-neighbor showed the fundamental ability to recognize ethanol, 2-propanol and their mixture.