SOME PECULIARITIES OBSERVED IN VOLTAMMETRIC STUDIES OF DIFFERENT GLASSY-CARBON ELECTRODES IN NONAQUEOUS MEDIA

Cyclic voltammograms for the ferric/ferrous reaction in prevailingly nonaqueous solutions, recorded with three electrochemically pretreated (ex situ) glassy carbon electrodes (GCEs) of low heat-treatment temperature (HTT), showed an unexpected increase in peak separations (Delta E(p)) with an increasing content of DMF or ethanol in the solution. This deactivating effect, which was minor with the Tokai was extremely pronounced with the GCEs of low HTT. In contrast to this, the Delta E(p) values obtained with these GCEs after their polishing with alumina showed a dramatic decrease with increasing content of the organic solvent. On the other hand, the Delta E(p) values for the voltammograms of the ferrocene/ferricinium reaction were practically independent of the nature and content of the organic solvent, electrode pretreatment mode, or the HTT value.