In order to monitor and control environmental pollution, there is an increasing need to develop new sensors able to detect toxic and hazardous gases. Liquid petroleum gas (LPG), a mixture of hydrocarbons, is an extensively used fuel, but there has been little work on LPG sensors. Now, scientists from Italy and India have fabricated a gas sensor, based on bulk semiconducting tin oxide and palladium, which is highly selective for LPG (A. R. Phani, S. Manorama and V. J. Rao, Mater. Chem. Phys ., 1999, 58, (2), 101-108).

The tin oxide based sensor, containing 1.5 weight per cent of palladium and 35 weight per cent of aluminum silicate, was produced by sintering at 800°C for five hours. It showed great sensitivity (0.97) towards the selective detection of LPG in air at 350°C, even in the presence of carbon monoxide and methane. Tests carried out over a six months period at 200-400°C gave consistent results, ±3 per cent, indicating its reliability with time.