Controlled potential electrolysis of inosine: Dependence of the selected potential on the nature of the electrooxidised products

The electrochemical oxidation of inosine has been studied in the phosphate buffers of different pH at pyrolytic graphite electrode (PGE). Voltammetric, coulometric, spectral studies and product analysis indicate that the oxidation occurs in an EC reaction involving a total of 6e, 6H+ per mole of inosine. As the Ep of inosine is close to background discharge, the controlled potential electrolysis was carried out at two potentials (at 100 mV higher and at peak potential) to avoid water oxidation reactions. Free radical pathways are more pronounced at higher potential leading to the formation of two tetramers, whereas, oxidation at peak potential in CPE leads to two dimers, two tetramers and an allantoin. The products of electrooxidation at exact peak potential were separated by HPLC and characterized by using GC–Mass, FT-IR, 1H NMR, m.p. A comparison of redox behaviour under two conditions is presented and tentative mechanism for the formation of products has also been suggested.