Design and Fabrication of Open-Tubular Array Gas Sensors Based on Conducting Polypyrrole Modified With Crown Ethers for Simultaneous Determination of Alkylamines

Some crown ethers, including 15C5, B15C5, 18C6, and DCy18C6, were used to modify nanostructure polypyrrole (PPy) film. Crown ether modified polypyrrole (PPy-C) gas sensor has been prepared by physical precipitation of crown ethers on surfaces of the PPy-polyester fibers. The morphology of the resulting PPy sensors was analyzed by scanning electron microscopy. The effect of the type of crown ethers on the conductivity and response patterns of the PPy-C sensors were studied. An array of sensors has been constructed using four modified polypyrrole sensors. The arrays were used for simultaneous determination of four types of amine, including butylamine, isobutylamine, propylamine, and isopropyl amine. The principal component analysis (PCA) has been used to test the orthogonalilty of the responses of the sensors. The results of the PCA technique revealed that the developed sensors are orthogonally sensitive to different types of amines. The 16 mixtures of amines were prepared and the responses of the array sensor were recorded for each mixture. A perceptron artificial neural network with 4-2-4 architecture has been used for correlating the responses of sensors to concentration of amines in gas phase. The developed multivariate model was used for simultaneous determination of amines and the relative standard errors were <10%. This paper suggests the applicability of Bayesian regularized neural networks as robust modeling techniques for correlating the responses of sensor arrays to concentration profiles of alkylamines.