Sensor Array for Detecting Odorous Compounds from Biodegradation Processes

This paper introduces the quartz microbalance (QMB) sensor technology, discusses its suitability for recording the concentration and composition of odorous gases, and compares it with other sensor types. The sensor array presented in this paper consists of six sensors with different coating materials. These host-guest-compounds can be calibrated to reach high levels of specificity for different analytes. Odours can be addressed as compositions of odorous gases. In order to find correlations between sensor signals and concentrations of odorous compounds, pattern recognition systems have to be applied to the output signal of a transducer. The system was extended by a preconcentration unit in order to attain higher levels of sensitivity. Because the system thus extended shows linear behaviour over a wide range of concentrations, pattern recognition has become easier. Evaluations in laboratory and field measurements proved the long-term stability of the system. Sensitivity was raised by a factor of 200, and the cross-sensitivity to water was lowered by a factor of 200 because water is not preconcentrated in the unit.