Determination of the working temperature of the MOS sensors used for the detection of ethanol and methanol

In this work, some peruvian red wines were analyzed using gas chromatography coupled to mass spectrometry (GC-MS) and it was determined that ethanol was the major volatile component present in the aroma (12 % in volume). followed by methanol (2-3 % in volume). Some MOS sensors based on SnO2 doped with Pd and Pt were prepared by precipitation with metallic charges from 0.1 to 0.5% and were tested with the same Peruvian wines. The stability and reproducibility of the sensing signal was analyzed at different working temperatures (200, 220, 240, 260 and 280 °C). The best working temperature at which the highest intensity of the response signal of the sensors was obtained at 260 ⁰C. In most of the cases studied, the sensing signal of the sensors was in general repetitive and stable, maintaining its amplitude and shape during long periods of the analysis. However, at the temperature of 280 ° C the signal loses intensity and in contact with methanol the signal is distorted.