Investigations on the performance of poly(o-anisidine)/graphene nanocomposites for the electrochemical detection of NADH

The electrocatalytic oxidation of dihydronicotinamide adenine dinucleotide (NADH) based on poly(o-anisidine)/graphene (POA/GR) nanocomposites modified glassy carbon electrode (GCE) was explored for the first time. POA/GR nanocomposites were synthesized via chemical oxidative polymerization method. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), high resolution transmission electron microscopy (HRTEM), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, and UV–Vis spectroscopy results demonstrate that nanocomposites are successfully synthesized. An intriguing composite structure was observed using different ratios of o-anisidine monomer and graphene. The electrical properties and electrochemical properties of these nanocomposites are investigated by impedance spectroscopy technique and cyclic voltammetric (CV) method, respectively. The synthesized nanocomposites were used to modify glassy carbon electrode (GCE), and the modified electrodes were found to exhibit electrocatalytic activity for oxidation of NADH at low potential range of + 0.045 V in a neutral environment. The fabricated sensor based on POA/GR31-modified GCE exhibited enhanced current response with very high sensitivity of 47.1 μA μM⁻¹ for the detection of NADH. The developed POA/GR-modified GCE exhibited excellent reproducibility, stability, and selectivity for the determination of NADH. The practical analytical utility of the proposed method was demonstrated by NADH spiked ascorbic acid (AA) and the results confirmed that the proposed method is suitable for the determination of NADH in the presence of AA. This can open up new opportunities for simple and selective detection of NADH and provide a promising platform for biosensor designs. - Highlights: • NADH sensor was prepared by poly(o-anisidine)/graphene nanocomposite modified GCE. • FESEM technique revealed the growth of POA nanofibers on the surface of graphene. • Good electrocatalytic activity of POA/GR modified GCE was obtained at pH 7.0. • High sensitivity and low detection limit for NADH detection was obtained. • Selective determination of NADH in the presence of ascorbic acid was achieved