The mechanism of electrochemical oxidation of rutin on a glassy carbon electrode was studied at different pH by using several electrochemical techniques (cyclic, linear sweep, differential pulse and square-wave voltammetry) in order to give deeper insight into the mechanism of electrochemical oxidation of rutin and adsorption of its oxidation products on a glassy carbon electrode. It was determined that the rutin oxidation process on a glassy carbon electrode is reversible, pH dependent and includes the transfer of 2 e– and 2 H+. The products of electrochemical oxidation strongly adsorb on the electrode surface. Maximum surface coverage, ?max, decreased with increasing scan rate from 3.4 × 10–9 mol cm–2 at scan rate 20 mV s–1 to 1.5 × 10–9 mol cm–2 at scan rate 100 mV s–1 and adsorption equilibrium constant was log K = 4.57 ± 0.05. Antioxidant properties of rutin were investigated by a Trolox equivalent antioxidant capacity (TEAC) assay. It was found that the TEAC values of rutin depend on concentration and the EC50 value of rutin amounted 0.23.

Department of Chemistry J J Strossmayer University F Kuhača 20 HR 31000 Osijek Croatia

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