Electrochemical oxidation of inosine-5′-triphosphate at pyrolytic graphite electrode

Abstract

The oxidation chemistry of inosine-5′-triphosphate (5′-ITP) has been investigated in phosphate containing supporting electrolytes of pH range 2.23–10.42 at pyrolytic graphite electrode (PGE). In cyclic voltammetry, a well-defined oxidation peak Ia was noticed over the entire pH range. The peak potential of peak Ia shifted to less positive potential when pH was increased. Concentration and sweep rate studies established the adsorption of 5′-ITP on the electrode surface. UV–vis spectral analysis indicated the formation of a UV-absorbing intermediates, generated during electrooxidation which decayed in a pseudo-first-order reaction having rate constant (k ∼ 0.672–0.783) × 10−3 s−1. The products were separated by HPLC and characterized by GC–MS, FT-IR, mp and 1H NMR as allantoin, C O O C, N N, C C bridged dimers, tetramer and ribose. A detailed interpretation of the redox mechanism of inosine-5′-triphosphate has been presented and a comparison of the observed electrochemical behavior with inosine indicated that Ep shifted to more positive potentials in the presence of phosphate groups. Many of the observed products were essentially similar to that observed during oxidation of inosine.