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T. Okada, K. Hiratani, H. Sugihara, and N. Koshizaki
[Sensors and Actuators B, Vol.13-14, pp.563-565, 1993]
A new type of solid state cation selective electrodes was proposed in which cation exchangers were incorporated in electrochemically polymerized pyrrole films deposited on solid electrodes (Fig.1). Pyrrole was polymerized anodically on Pt electrodes from solutions of pyrrole and naphthalenesulphonate compounds in acidic CH_{3}CN-H_{2}O mixed solvents. The composition of the CH_{3}CN-H_{2}O solvents was found to be an important factor in determining the emf characteristics of the electrodes. From the analysis of the film composition by XPS (X-ray photoelectron spectroscopy), it was revealed that the ratio of sulfur to nitrogen larger than 0.2 in the film was required for the appearance of Nernstian response to cationic activities. The possibility of constructing miniaturized cation-selective electrodes by means of an electrochemical procedure was demonstrated.
