THERMODYNAMICS AND KINETICS OF ADSORPTION AND ELECTROCATALYSIS OF NADH OXIDATION WITH A SELF-ASSEMBLING QUINONE DERIVATIVE

Platinum electrodes have been modified with the imine (I) derived from 3,4-dihydroxybenzaldehyde and 4-aminopyridine; a self-assembling mate rial which incorporates an o-hydroquinone moiety, and a pyridine group . This material adsorbs strongly onto polycrystalline platinum electro des through the pyridine nitrogen and the resulting modified electrode s retain the redox activity of the quinone/hydroquinone group. The the rmodynamics as well as the kinetics of adsorption of this material ont o platinum electrodes have been investigated and the apparent diffusio n coefficient (D-app) has also been measured. The modified electrodes exhibit potent and relatively persistent electrocatalysis for NADH oxi dation with a diminution of the overpotential of about 300 mV and the electrocatalytic current increases linearly with the NADH concentratio n from 0.2 mM to 2.0 mM.