Investigation of CO/CH4 mixture measured with differently doped SnO2 sensors

Arrays consisting of thick-film SnO2 sensors (based on three different materials and operated at two different temperatures) were exposed to mixtures of carbon monoxide (0, 3, 7 and 14 ppm), methane (0, 400, 1500 and 5000 ppm) and water (0, 30 and 50% RH at 25°C). It was possible to discriminate between different mixtures of CO and CH4 in the presence of different relative humidities in air. In addition, it was possible to quantify both CH4 and CO in the background of the other by using multivariate data analysis.