Selective Electrochemical Nanosensor based on Modified Carbon Paste Electrode for Determination of NADH in the presence of Uric Acid

The electrochemical properties of a modified carbon paste electrode with the synthesized compound of 2,2'-[1,7–heptanediylbis(nitrilomethylidene)]-bis(4-hydroxyphenol) (DHBH) and graphite nanoparticle (GN) were studied by cyclic voltammetry (CV), chronoamperometry and differential pulse voltammetry (DPV) methods. The proposed electrode shows excellent electrocatalytic activity towards the oxidation of NADH under the optimum pH of 7.0. The modifier and nanoparticle simultaneously lead to a reduce overpotential of NADH oxidation about 250 mV and enhance current about 6 μA of the unmodified CPE. This electrochemical sensor exhibited a detection limit (3σ) of 13.4 nM with two linear dynamic ranges (0.01-6.0 and 6.0-400.0 μM) for the determination of NADH. The modified electrode can detect well NADH (180 mV) in the presence of Uric acid (360 mV) simultaneously. Also, the performance of the proposed sensor was evaluated in real samples.