Detection of volatile compounds with mass-sensitive sensor arrays in the presence of variable ambient humidity

Mass-sensitive sensor arrays were established for the detection of isomeric or highly analogue analyte mixtures, which show similar physical and morphological properties. Supramolecular host-guest chemistry and arrays of four mass-sensitive quartz crystal microbalances have been successfully combined with multivariate calibration techniques in the presence of variable air moisture. This system enabled even the separation of xylene isomers-a task that might be crucial even by gas chromatography. The data of the sensor arrays were analyzed with partial least squares and artificial neural networks. The xylene isomers could be detected with an accuracy of ~1% in the range of 0-200 ppm, nearly eliminating the residual water cross- sensitivity of the sensor coatings, which allows effective work place or environmental monitoring of toxic compounds with fast response levels.