Electrodeposition of Cu2O nanoflower on the surface of FTO; Cu2O/FTO application in hydrodynamic amperometric determination of glucose

Diabetes is a chronic disease causing metabolic and systemic disorders. With more than 220 million people affected, diabetes has become one of the major health afflictions worldwide, andthe number of diabetes patients is expected to double in 20 years (1). Therefore, it is of significant importance to develop fast, accurate and stable technologies to detect glucose levels, both in vivo and in vitro, not only in blood but also in other sources such as foods andpharmaceuticals. There has been several efforts to fabricate nanosensors for determination of glucose using metals/metal oxides such as Cu, Ag, Pt, Cu2O, ZnO, RuO2, MnO2, and TiO2 using various fabrication techniques including sol–gel, electrodeposition and self-assembly (2). In thisstudy, nanoflowers of Cu2O was electrodeposited on the surface of FTO substrate. The asprepared Cu2O/FTO electrode was used as working electrode for hydrodynamic amperometric determination of glucose. The fabrication conditions of Cu2O/FTO nanoflowers anddetermination conditions of glucose were optimized. Fabrication of Cu2O/FTO. Cu crystals were electrodeposited on FTO in a solution containing0.05 M CuSO4 and 0.3 M lactic acid in a typical electrochemical cell equipped with a Pt wire counter electrode and Ag|AgCl|KCl (3 M) as reference electrode. The electrodeposition wascarried out with a rectangular potential pulsed mode at a potential of -2.0 V for 0.2 s, and then apotential of 0.0 V for 1 s, with various numbers pulses (10 to 150 pulses). The Cu-loaded FTO were then potentiostatically anodized in NaOH electrolyte at -0.2 V for 30 min at 25°C tofabricate Cu2O nanoflowers on FTO (3). Characterization of Cu2O/FTO surface morphology. The as-prepared electrodes surfacemorphologies was characterize with SEM images. In the Fig. 1, the SEM images of the electrodes were presented before (a) and after (b) anodization at -0.2 V in the NaOH solution. From this Figure, the fine structure of nanoflowers was seen after anodization of electrode surfaces.Optimization of Cu2O/FTO electrodeposition condition. The numbers of pulses (10 to 150), NaOH concentration (0.05 to 0.5 M), anodization time (5 to 60 min), adding of SDS surfactant (0 to 0.1 M) were effective factors, so this parameters were optimized and respectively 100 pulses,0.1 M, 30 min and 0 were optimized. Optimization of glucose determination condition. After optimization of electrode fabricationconditions, the effective parameters in hydrodynamic amperometric determination such as applied potential, NaOH concentration were optimized and the 0.6 V applied potential and 0.2 M NaOH were used as optimized condition.Finally, the hydrodynamic determination of glucose was performed in the optimized condition.The obtained results showed that linear dynamic range of determination was 1-4 mM and limit of detection of glucose was about 1.4×10-6 M.

کلیدواژه ها:

Electrodeposition ، Cu2O/FTO ، Glucose ، Hydrodynamic determination ، Nanoflowers