Use of a chromatographic column to improve the selectivity of the SnO2 gas sensors: first approach towards a miniaturised device and selective with hydrogen fluoride vapours

Tin dioxide-based gas sensors were laid out at the exit of a chromatographic column for the selective detection of hydrogen fluoride in the atmosphere. After having selected a stationary phase adapted to this particular molecule, the sensor's signals were studied using various experimental parameters. In this paper a complete description of the experimental device and of the electrical responses is given. For the experiment, the gas sample was formed by a gas mixture of HF, O2 and N2. It was found that the optimal mode of detection corresponds to the sensitive element (SnO2) having a temperature near to 500 °C with a carrier gas of oxidising nature (synthetic air). Moreover, it was found that with this experimental configuration, a minimum concentration of about 0.8 ppm was detectable.