MODIFICATION OF GLASSY-CARBON ELECTRODE SURFACES WITH MEDIATORS AND BRIDGE MOLECULES

Glassy carbon electrodes have been modified with the mediators di(n-aminopropyl)viologen (DAPV), p-benzoquinone (BQ), and with the bridge molecule ethylenediamine (EDA), by electrochemical oxidation of the electrode surface. The formation of reactive surface groups is probably involved. DAPV has been used as a model compound for the attachment of substances containing a primary aliphatic amine group. BQ could be attached to the electrode directly or by coupling to an EDA-modified electrode. Noradrenaline and NADH were attached to the EDA-modified carbon surface using glutaraldehyde. Two enzymes, Desulfovibrio vulgaris hydrogenase and horseradish peroxidase (HRP) showed mediated electron transfer with the DAPV- and BQ-modified electrodes, respectively. Electrodes modified with BQ and HRP were used in the amperometric mode for the determination of hydrogen peroxide in a flow injection analysis system.