Nonenzymatic amperometric determination of glucose by CuO nanocubes–graphene nanocomposite modified electrode

Here, we report a nonenzymatic amperometric glucose sensor based on copper oxide (CuO) nanocubes–graphene nanocomposite modified glassy carbon electrode (CuO–G–GCE). In this case, the graphene sheets were cast on the GCE directly. CuO nanocubes were obtained by oxidizing electrochemically deposited Cu on the graphene. The morphology of CuO–G nanocomposite was characterized by scanning electron microscopy. The CuO–G–GCE-based sensor exhibited excellent electrocatalytic activity and high stability for glucose oxidation. Under optimized conditions, the linearity between the current response and the glucose concentration was obtained in the range of 2 μM to 4 mM with a detection limit of 0.7 μM (S/N = 3), and a high sensitivity of 1360 μA mM− 1 cm− 2. The proposed electrode showed a fast response time (less than 5 s) and a good reproducibility. The as-made sensor was applied to determine the glucose levels in clinic human serum samples with satisfactory results. In addition, the effects of common interfering species, including ascorbic acid, uric acid, dopamine and other carbohydrates, on the amperometric response of the sensor were investigated and discussed in detail.