OXIDATION OF NITRIC-OXIDE AT A PORPHYRINIC-BASED SENSOR NEW RESULTS FROM ROTATING-DISK EXPERIMENTS

An amperometric sensor for the determination of nitric oxide based on its oxidation on a glassy carbon electrode modified with electropolyme rized vanillin porphyrin [tetrakis(3-methoxy-4-hydroxyphenyl)porphyrin ] film and Nafion is described. Our results show that the anodic oxida tion of NO at the modified electrode is the result of a catalytic effe ct induced by the porphyrinic modifier, that acts as a 3D system. The effect of film thickness of both porphyrinic modifier and Nafion on th e NO response is tested. The results of rotating disk electrode experi ments are presented and a general mathematical model of the working se nsor is also given.