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UPSI Digital Repository (UDRep)
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| Abstract : Universiti Pendidikan Sultan Idris |
| This study describes the fabrication and characterisation of modified glassy carbon electrode (GCE) with metal oxide/graphene nanocomposite using chemical reduction method in alkaline aqueous solution for detection of glucose. Two types of metal oxide/graphene nanocomposites have been synthesised in this study, namely cuprous oxide/graphene (Cu2O/graphene) nanocomposite and iron oxide/graphene (Fe3O4/graphene) nanocomposite. These nanocomposites were characterised by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, transmission electron microscopy and field emission scanning electron microscopy. The electrochemical properties of modified electrodes were examined using cyclic voltammetry, electrochemical impedance spectroscopy and chronoamperometry. The results show that the type of solvent used for casting the nanocomposite dispersion on electrode, pH, concentration of electrolyte, weight of nanocomposite dispersion casted on electrode and scan rate provided very crucial effects towards glucose oxidation. For amperometric studies, at an applied potential of +0.50 V, the Cu2O/graphene/GCE presented high sensitivity of 1330.05 μA/mM/cm2 and fast response within 3 s only. This amperometric non-enzymatic glucose sensor had a linear range from 0.01 to 3.00 mM glucose with detection limit of 0.36 μM. Meanwhile, by using the Fe3O4/graphene/GCE electrode under optimised conditions (+0.60 V), the detection limit was low at 0.18 μM with a linear range from 0.05 to 4.00 mM as well as good sensitivity (959.00 μA/mM/cm2), stability and reproducibility. For both modified sensors, the interference due to the presence of ascorbic acid, dopamine, uric acid and other carbohydrates was negligible. These proposed sensors were successfully applied for the determination of glucose concentration in real blood samples. Thus, it can be concluded that non-enzymatic modified GCE with Cu2O/graphene nanocomposite and Fe3O4/graphene nanocomposite are able to detect glucose. With characteristics such as high sensitivity, selectivity and repeatability, the electrodes are proposed as the appropriate alternative for the determination of glucose. |
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