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

• Nanoporous-PEDOT modified GCE for NADH oxidation for the first time.
• Modifier reduces overpotential of NADH oxidation ∼0.300 V.
• High resistance against fouling and twofold enhanced sensitivity observed.
• Detection limit is found to 3.8 μM with a sensitivity of 0.026 μA/μM.
• NADH detection in the presence of ascorbic acid is demonstrated.

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 0.1 M phosphate buffer solution (pH 7.0) containing 5 mM NADH. Studies revealed that nanoporous-PEDOT/GCE exhibited strong electrocatalytic activity on the oxidation of NADH with a decreased overpotential of about 0.318 V 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 × 10−6 cm2 s−1 and 1.09 × 102 M−1 s−1, respectively. Sensitivity of nanoporous-PEDOT/GCE is measured by amperometric method which showed linear variation in the concentration range between 5 and 45 μM at an applied overpotential of 0.5 V. Limit of detection (LOD) and sensitivity are found to be 3.8 μM and 0.026 μA/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 0.370 V 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.

Nanoporous-PEDOT modified GCE is established for NADH oxidation for first time. Here, it is observed that overpotential of NADH oxidation is reduced up to 0.318 V than GCE along with twofold enhanced sensitivity and high resistance against fouling property. Using this sensor platform the detection limit of 3.8 μM is achieved employing amperometric technique. Further, it is also possible to detect NADH in presence of ascorbic acid (peak separation between NADH and ascorbic acid >0.370 V). Therefore, the proposed method is simple, favourable, and reliable and also shows large potential applications in biosensors.Figure optionsDownload as PowerPoint slide