Metal Oxide Gas Sensor Arrays: Geometrical Design and Selectivity

Metal oxide gas sensors are commonly used in electronic noses. Their peculiarity, of altering the gas composition during the sensing process, is often not considered in planning the layout of the sensor chamber. However, for measurements with low flow rates (e.g. static headspace measurements) this effect can't be neglected. Results obtained with home made thick film sensors demonstrate the influence of consumption on the sensor signal. Depending on the sensor arrangement and the measurement conditions the selectivity of the whole system can be increased, respectively - for an inappropriate choice of the parameters - even decreased.