Electrochemical oxidation of 8-oxo-2'-deoxyguanosine on glassy carbon, gold, platinum and tin(IV) oxide electrodes

Cyclic voltammetry was used to investigate the oxidation of 8-oxo-2'-deoxyguanosine (8-oxo-dG) on the glassy carbon (GC), platinum, gold and SnO2 electrodes over a range of the sweep rate, 8-oxo-dG concentration and the solution pH. Reaction mechanism that is common to all these electrodes involves the two-electron two-proton charge transfer step followed by the irreversible chemical reaction(s). Rate of the charge transfer reaction decreases with the increasing solution pH (GC, Pt, Au), and depends on the nature of the electrode material following the sequence GC > Pt, Au > > SnO2. These effects can be related to the degree of oxidation of the electrode surface (Pt, Au, SnO2), or to the density of the active surface sites (GC). Any of these electrodes can be used for the fabrication of an amperometric detector for 8-oxo-dG.