Microwave-assisted synthesis of graphene modified CuO nanoparticles for voltammetric enzyme-free sensing of glucose at biological pH values

Abstract

The effect of graphene nanosheets on the glucose sensing performance of CuO powders was investigated. CuO and graphene-modified CuO nanoparticles (NPs) were fabricated by microwave-assisted synthesis and characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy. The material was placed on a glassy carbon electrode (GCE) which then was characterized by cyclic voltammetry and chronoamperometry with respect to the capability of sensing glucose both at pH 13 and pH 7.4. The results revealed that the modified GCE has a fast and selective linear response to glucose at pH 13 that covers the 0.21 μM to 12 mM concentration range, with a 0.21 μM low detection limit. The presence of graphene nanosheets results in an improved sensitivity which is to 700 μA mM^-1 cm^-2. In solution of pH 7.4, the respective data are a linear analytical range from 5 to 14 mM; a 5 μM LOD and a sensitivity of 37.63 μA mM^-1 cm^-2 at working potential of -0.05 V (vs. Ag/AgCl) and scan rate of 50 mV s^-1. Ascorbic acid, dopamine, uric acid, sucrose, maltose and fructose do not interfere. Graphical abstract ᅟ.

Keywords: Alkaline pH; Carbon nanomaterial; Chronoamperometry; Cyclic voltammetry; Electrochemical detection; Human blood serum; Metal oxide; Selective glucose detection, phosphate buffer; X ray photoelectron spectroscopy.