Voltammetric sensor array based on conducting polymer-modified electrodes for the discrimination of liquids

In this work, a novel type of voltammetric electrodes based on conducting polymers has been developed and used as sensing units of a sensory system. Polymeric sensors have been obtained by electrodeposition of the corresponding monomers (3-methylthiophene, aniline and pyrrole) onto platinum disks using a range of doping agents. The electrochemical response of polypyrrole electrodes is particularly rich and stable. Moreover, their electrochemical characteristics can be improved by using large anions or redox anions as dopants. A multichannel liquid sensor has been constructed using those sensors showing the best performances in terms of stability and variety of responses. The array of sensors has been exposed to solutions with distinct taste properties (sweet, bitter, acid, salty and astringent). Each sensor shows a characteristic electrochemical response when exposed to the studied solutions, providing a high degree of cross-selectivity. The principal component analysis (PCA) of the obtained signals has allowed the discrimination of the solutions tested. (C) 2004 Elsevier Ltd. All rights reserved.