Chemical sensors for water monitoring: diversity of approaches to behavioral modeling

Mathematical models of chemo-electrical characteristics of ion-sensitive chemical sensors is essential for development of measuring algorithms to be implemented in firmware of water probes. A crucial point of algorithms like these is a data fusion task, where a matrix of sensors sensitive to a matrix of ions give a matrix of electrical responses. Hence unknown ion activities may be calculated if a parameterized mathematical model of sensor is known. During three years of activity in FP6 WARMER project a diversity of physical and behavioral approaches to sensors modeling has been considered. Since a model selection influence accuracy of measurements, then a plenty of different modeling approaches was discussed and practically verified on the base of laboratory measurements of sensors. Some typical measurements have been used and verification of accuracy of existing has been performed. This contribution contains a discussion of possibilities of modeling of potentiometric sensors. Several physical and behavioral models have been taken into account. It has been shown that in data fusion application essential is small number of parameters and small calculation complexity since accuracy of model has not to be better than accuracy of sensors which is rather low. Hence we must focus on a trade-off between necessity of accurate modeling and availability of accurate sensors.