Alves Jorge, Sonia Maria [UNESP]Rodrigues Pontinha, Ana DoraMatos Marques, Maria PaulaOliveira-Brett, Ana Maria2014-05-202014-05-202010-01-01Analytical Letters. Philadelphia: Taylor & Francis Inc, v. 43, n. 10-11, p. 1713-1722, 2010.0003-2719http://hdl.handle.net/11449/19156The electrochemical redox behavior of usnic acid, mainly known for its antibiotic activity, has been investigated using cyclic, differential pulse and square wave voltammetry in aqueous electrolyte. These studies were carried out by solid state voltammetry with the solid mechanically attached on the surface of a glassy carbon electrode and at different pH values. Usnic acid did not present any reduction reaction. The pH-dependent electrochemical oxidation occurs in three steps, one electron and one proton irreversible processes, assigned to each of the hydroxyl groups in the molecule. Adsorption of the non-electroactive oxidation product was also observed, blocking the electrode surface. An oxidation mechanism was proposed and electroanalytical methodology was developed to determine usnic acid.1713-1722engElectrochemistryOxidationSolid state voltammetryUsnic acidArtigo10.1080/00032711003653890WOS:000280200400013Acesso restrito