Electrocatalytic oxidation of ascorbic acid by [Fe(CN)6]3-/4- redox couple electrostatically trapped in cationic N,N-dimethylaniline polymer film electropolymerized on diamond electrode

被引：33

作者：

Roy, Protiva Rani ^{[1
]}

Saha, Madhu Sudan ^{[1
]}

Okajima, Takeyoshi ^{[1
]}

Ohsaka, Takeo ^{[1
]}

机构：

[1] Tokyo Inst Technol, Dept Elect Chem, Interdisciplinary Grad Sch Sci & Engn, Midori Ku, Yokohama, Kanagawa 2268502, Japan

来源：

ELECTROCHIMICA ACTA | 2006年 / 51卷 / 21期

关键词：

electrocatalysis; ferricyanide; polymer film; ascorbic acid; amperometric sensor; diamond electrode;

D O I：

10.1016/j.electacta.2005.12.022

中图分类号：

O646 [电化学、电解、磁化学];

学科分类号：

081704 ;

摘要：

Multinegatively charged metal complex, hexacyanoferrate ([Fe(CN)(6)](4-)), was electrostatically trapped in the cationic polymer film of N,N-dimethylaniline (PDMA) which was electrochemically deposited on the boron-doped diamond (BDD) electrode by controlled-potential electrooxidation of the monomer. This ferrocyanide-trapped PDMA film was used to catalyze the oxidation of ascorbic acid (AA). Increase in the oxidation current response with a negative shift of the anodic peak potential was observed at the cationic PDMA film-coated BDD (PDMA vertical bar BDD) electrode, compared with that at the bare BDD electrode. A more drastic enhancement in the oxidation peak current as well as more negative shift of oxidation potential was found at the ferrocyanide-trapped PDMA film-coated BDD ([Fe(CN)(6)](3-/4-)vertical bar PDMA vertical bar BDD) electrode. This [Fe(CN)6](3-/4-)vertical bar PDMA vertical bar BDD electrode can be used as an amperometric sensor of AA. Ferrocyanide, electrostatically trapped in the polymer film shows more electrocatalytic activity than that coordinatively attached to the polymer film or dissolved in the solution phase. The electrocatalytic current depends on the surface coverage of ferricyanide, Gamma(Fe), within the polymer film. Diffusion coefficient (D) of AA in the solution was estimated by rotating disk electrode voltammetry: D = (5.8 +/- 0:3) x 10(-6) cm(2) s(-1). The second-order rate constant for the catalytic oxidation of AA by ferricyanide was also estimated to be 9.0 x 10(4) M-1 s(-1). In the hydrodynamic amperometry using the [Fe(CN)(6)](3-/4-)vertical bar PDMA vertical bar BDD electrode, a successive addition of 1 mu M AA caused the successive increase in current response with equal amplitude and the sensitivity was calculated as 0.233 mu A cm(-2) mu M-1. (c) 2005 Elsevier Ltd. All rights reserved.

引用

页码：4447 / 4454

页数：8

共 54 条

[1] KINETICS OF ELECTROCHEMICAL REACTIONS MEDIATED BY REDOX POLYMER-FILMS - IRREVERSIBLE CROSS-EXCHANGE REACTIONS - FORMULATION IN TERMS OF CHARACTERISTIC CURRENTS FOR STATIONARY TECHNIQUES [J].