Electronic nose based on the polymer coated SAW sensors array for the warfare agent simulants classification

A reference and three polymer coated surface acoustic wave sensors making an electronic nose were introduced. This system contained the pre-concentration unit in order for detection of low level warfare agent simulants. Principal component analysis (PCA), artificial neural network (ANN) and the combination of these two methods (PCA-ANN) were used for differentiation between the three classes including nerve and mustard simulants and mixtures of them. Different polymers including hexafluoro-2-propanol-substituted polysiloxane SXFA, poly(epichlorohydrin) PECH and phenyl methyl polysiloxane (75% phenyl and 25% methyl) OV25 were used as chemical interfaces and the obtained results were satisfactory. The loading plot of PCA showed that there were no sensors with the similar loadings and thus these three polymers had the enough and effective separated roles in differentiating between above-mentioned various gas classes. It was also proved that the ANN and PCA-ANN had good capability in pattern recognition of aforementioned gas classes. The fabricated system was successfully used for identification of single and binary samples of the three gas classes above- mentioned.