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Electrochemical sensor for superoxide anion radical using polymeric iron porphyrin complexes containing axial 1‐methylimidazole ligand as cytochrome c mimics
Author(s) -
Yuasa Makoto,
Oyaizu Kenichi,
Yamaguchi Aritomo,
Ishikawa Masuhide,
Eguchi Katsuya,
Kobayashi Tomohiro,
Toyoda Yuujiro,
Tsutsui Satoshi
Publication year - 2005
Publication title -
polymers for advanced technologies
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.61
H-Index - 90
eISSN - 1099-1581
pISSN - 1042-7147
DOI - 10.1002/pat.590
Subject(s) - porphyrin , electrochemistry , ligand (biochemistry) , supporting electrolyte , materials science , catalysis , inorganic chemistry , amperometry , electrolyte , imidazole , electrode , polymer chemistry , photochemistry , chemistry , organic chemistry , biochemistry , receptor
A needle‐type electrochemical sensor for the facile detection of superoxide anion radical (O 2 − . ) was devised using an electrodeposited film of a polymeric porphyrin complex attached to a carbon microelectrode which was placed in a stainless steel 18G needle tube as an auxiliary electrode. The sensing element was prepared by means of electropolymerization of bromoiron(III) meso ‐ tetra(3‐thienyl)porphyrin in the presence of 1‐methylimidazole in CH 2 Cl 2 containing 100 mM tetrabutylammonium perchlorate (TBAP) as a supporting electrolyte, which gave a smooth film of the corresponding polymer. The film was electrochemically active to give a redox response near −0.05 V versus Ag/AgCl due to the iron(II/III) couple. The microsensor was applied to detect O 2 − .produced by xanthine oxidation catalyzed by xanthine oxidase. The amperometric response for O 2 − .was monitored at an electrode potential of 0.5 V versus the auxiliary electrode in a 10 mM phosphate buffer. The microsensor displayed a high catalytic activity for the oxidation of O 2 − .and showed a linear relationship between the current and the O 2 − .concentration. Axial coordination of an imidazole ligand to the iron porphyrin center enhanced selectivity for O 2 − .by impeding the undesired coordination of H 2 O 2 that resulted from the dismutation of O 2 − . . Copyright © 2005 John Wiley & Sons, Ltd.