Electrocatalytic oxidation of NADH at low overpotential using nanoporous poly(3,4)-ethylenedioxythiophene modified glassy carbon electrode

Abstract

Nanoporous-poly(3,4)ethylenedioxythiophene (PEDOT) modified glassy carbon electrode (GCE) significantly lowers the overpotential and shows high resistance against fouling while oxidizing β-nicotinamide adenine dinucleotide (NADH). The electrocatalytic behaviour of nanoporous-PEDOT modified GCE was studied using cyclic voltammetry in 0.1M phosphate buffer solution (pH 7.0) containing 5mM NADH. Studies revealed that nanoporous-PEDOT/GCE exhibited strong electrocatalytic activity on the oxidation of NADH with a decreased overpotential of about 0.318V as compared to a bare GCE. In addition, chronoamperometric measurements were studied to understand the electron transfer kinetics of nanoporous-PEDOT/GCE which revealed an average diffusion co-efficient (D) and apparent rate constant (k) of 1.56×10−6cm2s−1 and 1.09×102M−1s−1, respectively. Sensitivity of nanoporous-PEDOT/GCE is measured by amperometric method which showed linear variation in the concentration range between 5 and 45μM at an applied overpotential of 0.5V. Limit of detection (LOD) and sensitivity are found to be 3.8μM and 0.026μA/μM, respectively. While quantifying the sensitivity of the electrode, it is found that the electrode surface fouling towards NADH oxidation decreased to an extent of 85%. Interference study is examined in the presence of ascorbic acid (AA) where a peak separation of more than 0.370V is observed between AA and NADH. Thus, nanoporous-PEDOT/GCE provides a simple platform for the oxidation of NADH at low overpotential with high resistance against fouling and without AA interference.