Electrochemical behaviour of NAD⁺ -modified carbon paste electrodes

Abstract

The effects of electrochemical pretreatment time on the electrochemical response of NAD⁺-modified carbon paste electrodes have been analysed. Prolonged pretreatment results in an improvement in the catalysis of NADH oxidation. First, pretreatment produces a remotion of pasting liquid that increases the number of surface sites for NADH oxidation. But this surface activation reaches a limiting value and, at longer pretreatment time, activation is produced by the contribution of reduced surface functionalities.NAD⁺-modified carbon paste electrodes have also been fabricated by incorporating appropriate quantities of NAD⁺ directly into the paste mixture. Analogous to solution-phase NAD⁺, the electrodes constructed in this manner present true surface active groups and are able to catalyse NADH oxidation. Prrtreatment does not result in a loss of their electrocatalytic properties.