INTERPRETING SIGNALS FROM AN ARRAY OF NONSPECIFIC PIEZOELECTRIC CHEMICAL SENSORS

Pattern recognition methods were tested using a gas sensor array consi sting of eight interchangeable quartz crystals coated with different s orbent layers, The system is designed in such a way as to allow headsp ace sampling from a jar or vial, Using a two-sample t-test the two sam pling methods were found to be significantly different at the 95% conf idence level, It was found that the application of principal component analysis, multivariate analysis of variance and discriminant function analysis to the gradient of the initial responses and over-all respon se magnitudes allowed hexane, o-xylene, toluene, dodecane and tetradec ane to be distinguished.