Title: Immobilization of Gold Nanoparticles on the Surface of Glassy Carbon Electrode and Electrocatalytic Oxidation of Ascorbic Acid at the Electrode
Abstract: Gold nanoparticle(GNP) modified glassy carbon electrode(GCE) was prepared first by covalent-linking,through electrochemical method,a monolayer of 2-aminoethanethiol(AET) on the surface of GCE,and then through intereaction of gold with the mercapto group at the terminal of AET molecule,to immobilize GNP on the surface of the GCE.This modified electrode was named abbreviately as GNP-AET/GCE.The structure and property of the GNP-AET/GCE were characterized by X-ray photoelectron spectroscopy and cyclic voltammetry.It was found that GNP-AET/GCE showed not only effective catalytic property to ascorbic acid in making a negative shift of its oxidation potential from 0.53 V(at bare GCE) to 0.33 V and a remarkable increase in oxidation peak current,but also a clear separation of the originally overlapped oxidation waves of ascorbic acid and dopamine at the bare GCE into 2 separate oxidation peaks,between which the potential difference attained to a value of 0.29 V.Based on these findings,a selective method for determination of ascorbic acid in the presence of dopamine by differential pulse voltammetry was proposed.Linear relationship between values of peak current and concentration of ascorbic acid was obtained in the range of 8.5×10-6-1.0×10-4mol·L-1,with its detection limit of 4.7×10-6mol·L-1.
Publication Year: 2008
Publication Date: 2008-01-01
Language: en
Type: article
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