Analyte identification using concentration modulation and wavelet analysis of QCM sensors

This paper describes a method for enhancing the discrimination that can be achieved with a quartz crystal microbalance (QCM) sensor in the identification of vapour phase analytes. The method is based on a controlled modulation of the analyte concentration, producing an output signal that contains information on the dynamic adsorption and desorption processes at the sensor interface. Analysis of the output signal by the discrete wavelet transforms (DWTs) yields the wavelet coefficients as the output features of this process and the clustering of these features can be used for analyte discrimination. The output of a single QCM sensor can then be used to discriminate between several selected analytes.