Investigation of the stability of piezoelectric chemical sensors

Gas chromatographic stationary phases were used as sensing materials on pie zoelectric quartz crystals. For characterisation of the selectivity, sensit ivity and stability changes of coated crystal sensors frequency measurement s and SEM methods were performed. Based upon the results, the ageing of the sensing materials could be characterised. Identification of volatile organ ic compounds was proved to be unreproducible using sensors after three mont hs. Due to the lack of sensitivity and the poor selectivity, the detectors could not be used to determine organic compounds. Increasing signal-to-nois e ratio and baseline drift were also observed. The lifetime of piezoelectri c chemical sensors using gas chromatographic stationary phases as sensing m aterials was found to be three months.