Selective Determination of Nicotinamide Adenine Dinucleotide (NADH) on Screen-Printed Polyethylene Terephthalate (PET) Electrodes Modified with a Reduced Graphene Oxide (rGO), Gold Nanoparticle (AuNP), and Poly-Methylene Blue Nanocomposite

The present work reports the development of a disposable nanocomposite-based amperometric sensor for reduced nicotinamide adenine dinucleotide (NADH). To fabricate disposable electrodes, conductive carbon and silver ink were screen-printed on a polyethylene terephthalate (PET) film substrate. The surface of the working electrode was modified with gold nanoparticles (AuNPs) decorated reduced graphene oxide (rGO) and subsequently electro-polymerized with methylene blue for the determination of NADH. The nanocomposite modified electrode decreases the potential for NADH oxidation with a significant increase in the current due to the synergy between AuNP and rGO. The developed electrochemical sensor determined NADH at 0 V versus pseudo-Ag/AgCl with linear relationships from 25 µmol L−1 to 1.0 mmol L−1 and 1.0 mmol L−1 to 10 mmol L−1. The sensor exhibits a good sensitivity of 35.49 µA/mmol L−1/cm2 and a detection limit of 6.61 µmol L−1 based upon a signal-to-noise ratio of 3. Furthermore, interferences from electroactive substances such as ascorbic acid and uric acid are eliminated at an oxidation potential of 0 V. Thus, the modified electrode provides a simple, selective, disposable, and low-cost approach for the amperometric determination of NADH.