Electrochemical Investigation of Glucose on a Highly Sensitive Nickel-Copper Modified Pencil Graphite Electrode

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 mu A mM(-1) cm(-2), and a low detection limit of 0.99 mu M 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 mu M 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.