ELECTRONIC NOSE

ELECTRONIC NOSE

ABSTRACT

The perception of volatile compounds by the human nose is of great importance in evaluating the quality of foods. Therefore, it is not surprising that repeated efforts have been made over the years to introduce instruments operating on a similar principle as the human nose: the “electronic nose” is an instrument that encloses the human sensitivity to the objectivity of the instrumental response and supplies results similar to the human nose and in short time.
An electronic nose is “an instrument which comprises an array of electronic chemical sensors with partial specificity and an appropriate pattern recognition system capable of recognising simple or complex odours”. It can be regarded as a modular system comprising a set of active materials which detect the odour, associated sensors which transduce the chemical quantity into electrical signals, followed by appropriate signal conditioning and processing to classify known odours or identify unknown odours. Research has been carried out into the use of thin and thick film semiconducting (inorganic and organic) materials for odour sensing. Research effort is now centered upon the use of arrays of metal oxide and conducting polymer odour sensors. The latter are particularly exciting because their molecular structure can be engineered for a particular odour-sensing application. The electronic nose finds wide applications in the food industry. Future developments in the use of hybrid micro sensor arrays and the development of adaptive artificial neural networking techniques will lead to superior electronic noses.