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 material which incorporates an o-hydroquinone moiety, and a pyridine group. This material adsorbs strongly onto polycrystalline platinum electrodes through the pyridine nitrogen and the resulting modified electrodes retain the redox activity of the quinone/hydroquinone group. The thermodynamics as well as the kinetics of adsorption of this material onto platinum electrodes have been investigated and the apparent diffusion coefficient (Dapp) has also been measured. The modified electrodes exhibit potent and relatively persistent electrocatalysis for NADH oxidation with a diminution of the overpotential of about 300 mV and the electrocatalytic current increases linearly with the NADH concentration from 0.2 mM to 2.0 mM.