SONOELECTROCHEMICAL STUDIES OF GUANINE AND GUANOSINE

The voltammetric behaviour of the purine base guanine and the correspo nding nucleoside guanosine at a glassy carbon electrode was investigat ed with the help of ultrasound. The adsorption of guanine and guanosin e as well as the adsorption of their oxidation products affects the ov erall voltammetric characteristics dramatically. Ln particular, the ef fect of ultrasound on the simultaneous adsorption of guanine and guano sine was studied in detail. Quantitative sonovoltammetric experiments show the number of electrons involved in the electro-oxidation of guan osine 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.