Single-preparation rGO/Cu–Cu2O nanocomposite-modified electrode integrating NaOH immobilized polymer blend film for one-step nonenzymatic glucose detection

Abstract

Nowadays, a one-step nonenzymatic glucose sensor with a portable detector system is still required for food quality control and food safety monitoring. This paper introduces a one-step nonenzymatic glucose sensor using a sodium hydroxide/polyvinyl alcohol/polyethylene oxide (NaOH/PVA/PEO) blend film integrating a reduced graphene oxide composited with a copper-based-nanoparticle (rGO/Cu–Cu2O)-modified electrode. The NaOH/PVA/PEO blend film facilitated direct measurements of real samples without sample preparation and pretreatment. A single-step preparation of the rGO/Cu–Cu2O nanocomposite-modified electrode was easily performed by electrodeposition via amperometry. The rGO/Cu–Cu2O deposited on the electrode surface was confirmed by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, confocal microscopy, and electrochemical characterization. The analytical performance of the proposed rGO/Cu–Cu2O-modified electrode was also compared with the CuO/rGO-modified electrode using commercial CuO nanoparticles. The glucose measurements were achieved by singly dropping glucose on the sample inlet well and detecting with amperometry using a small portable potentiostat connecting to a PStouch app with an overall analysis time of 180 s after sample loading. Linearity was observed in the range of 0.01–7 mM with a limit of detection of 0.06 μM. The proposed sensor with high storage stability (up to 56 days) was directly applied to measure the glucose levels in beverages, demonstrating promising results corresponding to the labeled values of the beverage products. Eventually, the proposed sensor is an alternative tool for one-step nonenzymatic glucose measurements to precisely control the glucose content in foods and beverages.