Direct modification of a glassy carbon electrode with toluidine blue diazonium salt: Application to NADH determination and biosensing of ethanol

摘要

We describe here the covalent modification of a glassy carbon electrode with toluidine blue (TB) diazonium salt, which is generated in situ from the reaction between the aromatic amino phenyl group of TB and sodium nitrite. TB is attached directly to the electrode surface without any cross-linking agent or complex matrices. The resulting TB films exhibit excellent electrocatalytic behavior toward NADH oxidation. Low potential detection of NADH is performed at 0.15V vs. Ag/AgCl. Furthermore, an ethanol biosensor is developed using the TB modified electrode and alcohol dehydrogenase. The great stability and reusability, excellent electrochemical reversibility, technically simple preparation and short preparation time make this method suitable for low-cost bioelectronical devices.