Sonoelectrochemical studies of guanine and guanosine

The voltammetric behaviour of the purine base guanine and the corresponding nucleoside guanosine at a glassy carbon electrode was investigated with the help of ultrasound. The adsorption of guanine and guanosine as well as the adsorption of their oxidation products affects the overall voltammetric characteristics dramatically. Ln particular, the effect of ultrasound on the simultaneous adsorption of guanine and guanosine was studied in detail. Quantitative sonovoltammetric experiments show the number of electrons involved in the electro-oxidation of guanosine to be two. Sonovoltammetry, i.e. the combination of voltammetry and ultrasonic irradiation, is demonstrated to be a useful approach to control the extent of adsorption of the relevant species and to avoid electrode fouling. This allows the development of reliable analytical procedures for the determination of guanine and guanosine, which are described in detail. (C) 1997 Elsevier Science S.A.