Synthesis and Characterization of a CuNi/graphene Oxide Nanocomposite for Non-enzymatic Glucose Detection

Background: Electrochemistry technique has attracted significant attention over the past decade as a potential candidate for the highly sensitive detection of analyte species. Objective: The goal of the present work is to fabricate a novel electrochemical non-enzymatic glucose sensor based on the nickel-copper/graphene oxide-modified glassy carbon electrode (Ni- Cu/GO/GCE). Method: A bare GCE was coated with graphene oxide, and then immersed in a deoxygenated solution containing 50 mM NiCl2 and 50 mM CuCl2 for the electrodeposition at -0.6 V for 100 s. The modified electrode's morphology and electrochemical performance were characterized using scanning electron microscopy and cyclic voltammetry, respectively. Results: The Ni-Cu/GO/GCE was found to exhibit a higher electrocatalytic activity for glucose oxidation than did a nickel/graphene oxide-modified GCE in an alkaline solution. When used as a glucose sensor, the electrode exhibited a sensitivity of 160.37 μA mM^-1 cm^-2 for glucose oxidation with a linear range from 15 μM to 1030 μM and a detection limit of 2 μM. The sensor was highly selective for glucose even in the presence of common interfering species such as ascorbic acid, uric acid, and dopamine. As a demonstration of its practicality, the Ni-Cu/GO/GCE was used to measure glucose in fetal bovine serum. Conclusion: A non-enzymatic glucose sensor based on the Ni-Cu/GO/GCE with high sensitivity and improved specificity was developed and characterized. Selective detection of glucose in a linear concentration range of 15-1030 μM was obtained. The proposed method has potential to be applied for accurate measurement of glucose level in real samples.