Catechin electrochemical oxidation mechanisms Janeiro, Patricia; Oliveira Brett, Ana Maria 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANTIOXIDANTS; ELECTROCHEMISTRY; ELECTRON TRANSFER; FLAVONOIDS; OXIDATION; PYROCATECHOL; RADICALS; RESORCINOL; VOLTAMETRY The oxidation of flavonoids is of great interest because of their action as antioxidants with the ability to scavenge radicals by electron transfer processes. The electrochemical oxidation of the flavonoid (+)-catechin, was investigated, over a wide range of conditions, using cyclic, differential and square wave voltammetry. The oxidation mechanism proceeds in sequential steps, related with the catechol and resorcinol groups and the oxidation is pH dependent. The oxidation of the catechol 3',4'-dihydroxyl electron-donating groups occurs first, at very low positive potentials, and is a reversible reaction. The hydroxyl groups of the resorcinol moiety oxidised afterwards were shown to undergo an irreversible oxidation reaction. (+)-Catechin also adsorbs strongly on the electrode surface and the final oxidation product is not electroactive and blocks the electrode surface. Netherlands 2004-08-02 English Journal Article Journal Name: Analytica Chimica Acta; Journal Volume: 518; Journal Issue: 1-2; Other Information: DOI: 10.1016/j.aca.2004.05.038; PII: S0003267004006506; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); PBD: 2 Aug 2004 Medium: X; Size: page(s) 109-115 https://doi.org/10.1016/j.aca.2004.05.038 [] 1-2 518 Journal ID: ISSN 0003-2670; ACACAM; TRN: NL05R4290067501 NLN 2010-12-31 20624422