Sniffers Inc

Published: Saturday 15 November 1997

An electronic nose would sniff whether tea is being spoiled in the drier, tomatoes have lost flavour or mangoes are about to ripen. Researchers at the University of Greenwich and the Natural Resources Institute of Chatham, UK, have developed the device that has sensors for carbon monoxide, ethylene, hydrogen sulphide, propane, ethanol and volatile organic compounds. The sensors are semi-metal oxides, mostly tin. When electricity is passed through the sensors, the electrical resistance changes according to the odour present in a given product. The variations in resistance create patterns characteristic of different varieties of tomato, mangoes and tea. The device can distinguish between varieties of tomatoes and teas better than chemical tests.

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