The electrochemical behaviour of 2,8-dihydroxyadenine (2,8-DHA)- the main adenine oxidation product-has been investigated over a wide pH range at a glassy carbon electrode (GCE) using cyclic, differential pulse and square wave voltammetry. The oxidation of 2,8-DHA is a quasi-reversible process, pH dependent and occurs with the formation of a main oxidation product, P-2,P-8-DHA, that strongly adsorbs on the electrode surface. The reduction of 2,8-DHA also occurs and is a reversible process in the absence of molecular oxygen. In electrolytes with pH between 4 and 9 two consecutive reversible charge transfer reactions were identified. However, it was observed that 0, interfered with the reductive electron transfer process of 2,8-DHA and that, in the presence of oxygen, the reduction of 2,8-DHA occurs at less negative potentials than in the absence of oxygen. (c) 2006 Elsevier B.V. All rights reserved.