On the adsorption and electrochemical oxidation of flavones apigenin and acacetin at a glassy carbon electrode

The electrochemical behaviour of flavones apigenin and acacetin was studied over a wide pH range using a glassy carbon electrode. The oxidation of both compounds is irreversible, pH dependent and occurs with the transfer of one electron and one proton from the hydroxyl group in their structures. The formation of two redox products that are reversibly oxidised was observed. The adsorption of apigenin and acacetin at the glassy carbon surface was also evaluated. It has been shown that, depending on solution concentration and/or adsorption time, the molecules can adopt different orientations influencing the peak potentials and their redox behaviour. The redox properties of apigenin and acacetin were discussed in respect to their conformations, functional groups attached to their structures, and to the isomer genistein.