The oxidation of beta-nicotinamide adenine dinucleotide (NADH) at poly(aniline)-coated electrodes Part II. Kinetics of reaction at poly(aniline)- poly(styrenesulfonate) composites

Poly(aniline)-poly(styrenesulfonate) composite-coated glassy carbon electro des are shown to produce a stable, reproducible amperometric response to NA DH in citrate-phosphate buffer at pH 7. These responses have been studied a s a function of electrode potential, film thickness and both NADH and NAD() concentration. The results show that the oxidation of NADH occurs through out the whole of the film and that NAD(+), the reaction product, reversibly inhibits the reaction. Rate constants for the different processes have bee n obtained by kinetic modelling and compared with those previously determin ed for poly(aniline)-poly(vinylsulfonate) films. Preliminary comparisons im ply that diffusion within 'pores' in these poly(aniline) composite matrices is important in determining the magnitude of the amperometric responses. ( C) 2000 Elsevier Science S.A. All rights reserved.