Odours and flavours identified with hybrid modular sensor systems

Hybrid sensor systems contain different types of chemical sensors whereby each type (transducer principle) contains an array of individual sensors. This leads to a large flexibility in the choice of transducers and sensor materials with the general aim of optimising the analytical performance of the total system. This concept makes it possible to optimise the quantitative analysis of mixtures of known gases as it will be demonstrated for mixtures of volatile organic compounds (VOCs). Alternatively this makes it possible to optimise the system for characterising odours and flavours. This will be demonstrated for different plastic as well as textile materials used in car industries and for different products of food industries, i.e. coffees, tobaccos, whiskeys, and olive oils. In our modular sensor systems we used arrays of different semiconductor gas sensors (based on metal oxides), of polymer coated quartz microbalance (QMB) sensors, of calorimetric sensors and of electrochemical sensors. with an option to add metal oxide semiconductor field effect transistor (MOSFET) sensors, These arrays are arranged as separate components in a modular sensor system 'MOSES'. For the qualitative discrimination of different odour samples a headspace-autosampler was added and transient sensor signals were monitored, The use of different transducer principles is shown to be essential for an unequivocal identification of odours and flavours. (C) 1997 Elsevier Science S.A.