3.2. Voltammetric behaviors of Ade and Gua at ACSE
The linear and cyclic sweep voltammetry of Gua and Ade in solutions indicated that these compounds exhibited just small anodic peaks at the inactivated carbositall electrode. It was found, however, that the electrochemical activation of the electrode surface reduced the oxidation potential and improved the electron transfer rates of oxidation reactions of both nucleobases. In case of the ACSE, well-defined anodic peaks were obtained, which corresponded to totally irreversible oxidation of Gua and Ade over the wide pH range (1–9). ABSs, BRBSs and PBSs were tested a supporting electrolyte in order to find the appropriate medium for the oxidation of both analytes. The best results were obtained by using PBS. It was found that both peaks potential (Ep) and peaks current (ipa) of Gua and Ade depended on the pH of 0.1 M PBS. The typical anodic voltammograms of these compounds at the ACSE are illustrated in Fig. 4.