Electrochemical Oxidation of Pyrogallol: Formation and Characterization of Long-Lived Oxygen Radicals and Application To Assess the Radical Scavenging Abilities of Antioxidants
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- 作者：Shaolin Mu ; Chong Chen
- 刊名：The Journal of Physical Chemistry B
- 出版年：2012
- 出版时间：October 18, 2012
- 年：2012
- 卷：116
- 期：41
- 页码：12567-12573
- 全文大小：336K
- 年卷期：v.116,no.41(October 18, 2012)
- ISSN：1520-5207
文摘
Electrochemical oxidation of pyrogallol in a pH 5.0 phosphate buffer was carried out on a reduced graphene oxide/glassy carbon (RGO/GC) electrode. Reduced graphene oxide plays an important role in catalyzing the electrochemical oxidation of pyrogallol. A deep yellow film deposited on the electrode exhibits electroactivity in a wide pH range. On the basis of the experimental results from measurements of 1H NMR, 13C NMR, and IR spectra, there are hydroxyl, carbonyl, and aldehyde groups in the product. No visible absorption peak occurs in the UV鈥搗is spectrum of the product, and its molecular weight is lower than that of the dipolymer but higher than that of the monomer. Therefore, the film is neither a polymer nor a dipolymer and is only a product of pyrogallol oxidation with oxygen radicals. No tendency toward the decay of the ESR signal intensity of the electrogenerated film deposited on the RGO/graphite electrode was observed after 210 days. Electrogenerated film was used as a radical source to test the radical scavenging abilities of ascorbic acid, catechin, and catechol in aqueous solutions based on the ESR signal intensity. The result indicates that ascorbic acid and catechin can scavenge the free radicals, but catechol can hardly scavenge the free radicals.