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
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
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DOI：
10.1016/j.electacta.2005.12.022
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发表时间：
2006-06
影响因子：
6.6
通讯作者：
P. Roy;M. Saha;T. Okajima;T. Ohsaka
中科院分区：
文献类型：
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作者：
P. Roy;M. Saha;T. Okajima;T. Ohsaka
N，N-二甲基苯胺阳离子聚合物膜通过控制电位电氧化将多负电荷金属络合物[Fe(CN)6]4-−捕获在含硼金刚石电极上。将亚铁氰化物捕获的PDMA膜用于催化抗坏血酸(AA)的氧化。与裸电极相比，阳离子PDMA膜包覆BDD(PDMA|BDD)电极的氧化电流响应增加，氧化峰电位负移。[Fe(CN)6]3−/4−|PdMA|BDD电极的氧化峰电流明显增强，氧化电位负移。这种[Fe(CN)6]3−/4−|PDMA|BDD电极可以作为AA的安培传感器。静电捕获在聚合物膜中的亚铁氰化物比配位附着在聚合物膜上或溶解在溶液相中的亚铁氰化物具有更强的电催化活性。电催化电流取决于聚合物膜中铁氰化物ΓFe的表面覆盖度。用旋转圆盘电极伏安法测得AA在溶液中的扩散系数为：D=(5.8±0.3)×10−6cm2s−1。在[Fe(CN)6]3−/4μ|PDMA|bdd电极的流体动力安培法中，加入1μMA可使电流响应等幅递增，其灵敏度为−μ2−1。
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 electro-oxidation 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|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−|PDMA|BDD) electrode. This [Fe(CN)6]3−/4−|PDMA|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, ΓFe, within the polymer film. Diffusion coefficient (D) of AA in the solution was estimated by rotating disk electrode voltammetry: D=(5.8±0.3)×10−6cm2s−1. The second-order rate constant for the catalytic oxidation of AA by ferricyanide was also estimated to be 9.0×104M−1s−1. In the hydrodynamic amperometry using the [Fe(CN)6]3−/4−|PDMA|BDD electrode, a successive addition of 1μM AA caused the successive increase in current response with equal amplitude and the sensitivity was calculated as 0.233μAcm−2μM−1.