کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
195500 | 459815 | 2006 | 8 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: 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](/preview/png/195500.png)
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) × 10−6 cm2 s−1. The second-order rate constant for the catalytic oxidation of AA by ferricyanide was also estimated to be 9.0 × 104 M−1 s−1. In the hydrodynamic amperometry using the [Fe(CN)6]3−/4−|PDMA|BDD electrode, a successive addition of 1 μM AA caused the successive increase in current response with equal amplitude and the sensitivity was calculated as 0.233 μA cm−2 μM−1.
Journal: Electrochimica Acta - Volume 51, Issue 21, 1 June 2006, Pages 4447–4454