title: Voltammetric and impedance studies of inosine-5'-monophosphate and hypoxanthine.
abstract: The oxidation mechanism and adsorption of inosine 5'-monophosphate and hypoxanthine were investigated in solutions of different pH using voltammetric and impedance methods at glassy carbon electrodes. For both compounds, the pH dependence from differential pulse voltammetry showed that the same number of electrons and protons are involved in the rate-determining step of the electrochemical reaction. In the case of hypoxanthine, it was also possible to study the effect of different concentrations. At high concentrations of hypoxanthine, two oxidation peaks were observed, the first due to hypoxanthine oxidation with formation of oligomers and the second due to hypoxanthine oligomer oxidation, both compounds adsorbing strongly. Impedance measurements corroborated the voltammetric results and enabled the study of the adsorption of hypoxanthine on glassy carbon.
authors.affiliation: Departamento de Química, Fac. Ciencias e Tecnologia, Universidade de Coimbra, 3004-535 Coimbra, Portugal. brett@ci.uc.pt
authors.forename: Ana Maria
authors.initials: AM
authors.lastname: Oliveira-Brett
authors.forename: Luís A
authors.initials: LA
authors.lastname: Silva
authors.forename: Giosi
authors.initials: G
authors.lastname: Farace
authors.forename: Pankaj
authors.initials: P
authors.lastname: Vadgama
authors.forename: Christopher M A
authors.initials: CM
authors.lastname: Brett
mesh_terms: D000327:Adsorption; D015374:Biosensing Techniques; D002244:Carbon; D017097:Electric Impedance; D004563:Electrochemistry / Q000295:instrumentation; D004566:Electrodes; D006863:Hydrogen-Ion Concentration; D019271:Hypoxanthine / Q000737:chemistry*; D007291:Inosine Monophosphate / Q000737:chemistry*; D010084:Oxidation-Reduction; D013499:Surface Properties
chemical_list: D007291:Inosine Monophosphate; D019271:Hypoxanthine; D002244:Carbon