In this study, a low‐cost, disposable, sensitive and selective electrochemical sensor was developed for glucose determination, which is based on a pencil graphite electrode (PGE) modified with nickel hydroxide. Cyclic voltammetry was used to deposit nickel on PGE. The morphology and composition of the unmodified and modified PGE electrodes were characterized by field‐emission scanning electron microscopy (FE‐SEM), atomic force microscopy (AFM) and energy‐dispersive X‐ray spectroscopy (EDX). The performance of the as modified electrode towards the electrooxidation of glucose in alkaline media was evaluated with cyclic voltammetry and amperometry techniques. A linear relationship between the concentration of glucose and oxidation peak currents was observed in two concentration ranges of 0.004–3.5 mM and 3.5–9.0 mM. The detection limit was 2 μM at signal‐to‐noise ratio of 3. In addition to a fast response time (<2 s), the proposed sensor preserved 93 % of its original response towards glucose after 28 days. Also, the sensor showed a good reproducibility and high selectivity for glucose oxidation in the presence of common interfering species. The use of Ni(OH)2/PGE sensor was successfully tested in the determination of glucose in human blood serum for the first time in the literature.
Novel nickel‐copper modified pencil graphite electrode (Ni−Cu/PGE) was fabricated and used as non‐enzymatic sensor for glucose determination. Ni and copper were electrodeposited on PGE using cyclic voltammetry. Morphology and composition of the modified PGE electrode were characterized by field‐emission gun scanning electron microscopy (FEG‐SEM), energy‐dispersive X‐ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT‐IR). Electrochemical oxidation of glucose was evaluated by cyclic voltammetry as well as by amperometry. Electrochemical measurements indicate that the Ni−Cu/PGE exhibits a high sensitivity of 2951 μA mM−1 cm−2, and a low detection limit of 0.99 μM which are, respectively, three times higher and twice lower than that on Ni/PGE prepared in the same conditions. Moreover, Ni−Cu/PGE exhibits a wider linear range from 1 to 10000 μM with a rapid response time within 2 s. Moreover, Ni−Cu/PGE showed a remarkable stability. The electrode was successfully applied for determination of glucose concentration in human blood without significant interference from potential endogenic interferents. The good applicability of the elaborated sensor made Ni−Cu/PGE promising for the development of effective and inexpensive non‐enzymatic glucose sensor.
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