SnO2 thin film chemical sensor as detector for capillary gas-chromatography of organic volatile compounds

A prototype solid state detector (SSD) for capillary gas-chromatography was realised using an experimental tin oxide thin film gas sensor doped with Au. The sensor, developed by LAMEL laboratories, was originally designed for VOC detection in air. The use of this kind of sensor in high-resolution capillary chromatography poses some demands on the performance of the sensor and the whole detector system, particularly those related to response speed and sensitivity. The sensor was mounted in a glass microchamber (1.2 ml) and installed on a gas-chromatographic system equipped with a flame ionisation detector (FID). The SSD was tested with ethylene and acetylene injections. The SSD response was evaluated measuring the sensor conductance shift versus time. The sensitivity for acetylene was quite higher than ethylene, accounting for the high reactivity of the former to oxidative reaction. The width of the chromatographic SSD peaks was measured at different sensor temperatures. This SSD detector implementation demonstrates the ability to detect 21 pg of acetylene.