Determination of Dopamine by Differential Pulse Voltammetry with Au Nanotubes Array Modified Glassy Carbon Electrode

Using polycarbonate template as working electrode, gold nanotubes were prepared by electro-deposition from a solution of HAuCl4 and HClO4. The template deposited with Au nanotubes was fixed on surface of glassy carbon electrode (GCE) and the GCE modified with arrayed Au nanotubes was prepared by dissolving the template from the electrode with CHCl3 for 7 min. The electrochemical behavior of dopamine (DA) at the modified electrode was studied by cyclic voltammetry (CV) and differential pulse voltammetry (DPV). It was found that DA showed a pair of oxidation and reduction peaks at the modified electrode. A sensitive method for determination of DA by DPV was proposed. Linear relationship between values of oxidation peak current at +0.170 V and concentration of DA was obtained in the range of 4.95×10-7-9.9×10-2mol·L-1, with detection limit (3σ) of 1.06×10-8mol·L-1. The proposed method was applied to the determination of DA in human urine, giving values of recovery and RSD′s (n=5) in ranges of 96.9%-101.4% and 3.1%-4.2% respectively.