The behavior of polypyrrole doped with different anions as an ion-selective electrode

Polypyrrole (PPy) films were electrochemically deposited on glassy carbon from aqueous solutions of different sodium salts (F−, Cl−, NO 3−, HSO 4−). Methods applied were potentiostatic polymerization or cyclic voltammetry. The electrochemical behavior of such electrodes was studied by cyclic voltammetry. The results obtained show that the reaction is localized at the electrode surface for polypyrrole doped with CI− and NO 3−, anions and diffusion‐controlled for F− anions. The polypyrrole films, examined as ion‐selective electrodes in solutions of anions corresponding to the dopant ones, exhibit lower or higher deviation from the Nernstian response depending on the dopant. When polypyrrole doped with HSO 4− was tested, a cationic response was obtained. The chemical exchange process of dopant anion was studied. The results show that this process depends on the nature of the dopant anion and the anion from the solution.