OVEROXIDIZED RROLE-CO-[3-(PYRROL-1-YL)PROPANESULFONATE])-COATED PLATINUM-ELECTRODES FOR SELECTIVE DETECTION OF CATECHOLAMINE NEUROTRANSMITTERS

The cation-exchange and anion-exclusion properties of the ole-co-[3-(p yrrol-1-yl)propanesulfonate]}-(PPy-PS) copolymer are exploited for imp arting higher selectivity to measurements of primary neurotransmitters in the presence of ascorbic acid. Such incorporation of ionizable sul fonated groups in the pyrrole ring prior to its electropolymerization leads to effective rejection of the anionic ascorbate species and pref erential collection of the cationic dopamine and norepinephrine. Overo xidized PPy-PS films thus offer better discrimination against ascorbic acid than Nafion or overoxidized polypyrrole coatings. Experimental v ariables influencing the permselective behavior of the PPy-PS layer, i ncluding the electropolymerization time and solution pH, were explored . The selectivity and sensitivity improvements associated with the inc reased electrostatic character of overoxidized polypyrrole films hold promise for neurochemical electrochemical studies.