Effects of solvent composition on the preparation and electroanalytical behaviors of polypyrrole modified electrodes

Conducting polypyrrole modified electrodes incorporated with alizarin red S ligands were prepared by electropolymerization of pyrrole in mixtures of water and acetonitrile. Electroanalysis of copper(II) species was performed voltammetrically. The effects of solvent systems employed for pyrrole electrodeposition on the electroanalytical behaviors of the modified electrodes were evaluated in terms of the pyrrole polymerization charge, alizarin red S coverage, copper response, and the ligand-to-metal ratio for copper analysis. Experimental results showed that the water content in the solvent mixture had strong influence on the electroanalytical performance of the polypyrrole modified electrodes. The morphology of the polypyrrole films prepared in different acetonitrile–water mixtures was examined and it indicated that there was close correlation between the film morphology and the electroanalytical behavior for copper(II) determination.