Carbon electrodes in amine analysis: Effect of chemically modified carbon surfaces on signal quality and reproducibility

The preparation of chemically modified graphite electrodes by various chemical treatments is described. These electrodes were tested with chlorpromazine, cyclopiroxolamine, sulfathiazole, bamipine, sparteine and diphenhydramine by differential pulse voltammetry. Compared with the unmodified and freshly polished carbon electrodes, the modified ones exhibit attractive properties such as enhanced stability against film formation. The initial signals at untreated electrodes are very high and decrease rapidly, but at pretreated electrodes the stability of the signals is usually improved. Adsorption and poisoning by film formation is suppressed by giving the surface of the electrode a chemical identity by chemical pretreatment. The improvements are not general but individual ones.