Application-specific design of a piezoelectric chemosensor array

Abstract A piezoelectric quartz sensor array with non-selective but different sensitive coating materials is used for the analysis of anaesthetic gases. Several gas-sensitive quartz resonators can be composed into an array and the sensor signals can be handled by pattern-recognition (PARC) methods. The steady-state single-sensor signals and the dynamic responses of the sensors can be calculated and processed using the partition coefficient and the heat of adsorption, respectively. Identification of different narcotics like halothane, enflurane, isoflurane and sevoflurane is achieved by classification of the gases in the discriminant plane with PARC methods. The sensitivity and selectivity of a piezoelectric gas sensor can be influenced by the selection of the absorptive coating materials. Substances used as gas chromatographic stationary phases are found to be useful as gas-sensitive coatings for the quartz resonators. Together with the pattern-recognition method, the above-mentioned parameters describing the function of the coating can be used, e.g., to increase the number of gases that can be identified with the chemosensor array. To achieve different cross-sensitivities of a redesigned sensor array determined by back-transformation of the signal patterns from the feature space, the gas chromatographic coating materials can be selected by means of the partition coefficient value. With this parameter an optimal design of the piezoelectric chemosensor array with respect to sensitivity and selectivity is possible.