The effects of concentration and solution pH on the kinetic parameters forthe electrocatalytic oxidation of dihydronicotiamide adenine dinucleotide (NADH) at glassy carbon electrode modified with electropolymerized film of toluidine blue o

The kinetic parameters for electrocatalytic oxidation of dihydronicotiamide adenine dinucleotide (NADH) at poly(toluidine blue o) (PTOB) modified glas sy carbon electrode have been determined using rotating disk electrode meas urements. The rate constant for the chemical reaction between NADH and PTOB was strongly influenced by NADH concentration and solution pH, and it decr eased with increasing NADH concentration. It is indicated that the electroc atalytic process proceeded via the formation of an intermediate charge-tran sfer complex between NADH and PTOB. The presence of Mg2+ and Ca2+ in an ele ctrolyte can greatly enhance the electrocatalytic current for NADH oxidatio n. (C) 2000 Elsevier Science B.V. All rights reserved.