Abstract:

Hydrothermally prepared zinc oxide nanorods were characterized by scanning electron microscopy and infrared spectroscopy. The zinc oxide nanorod modified graphite electrode was prepared by intercalation for dopamine determination. Voltammetric behavior and reaction mechanism of dopamine at the modified graphite electrode were investigated with cyclic voltammetry and differential pulse voltammetry. The results showed that there were good voltammetric responses for dopamine at the modified electrode under optimal conditions, with peak currents greatly enhanced and an negative shift of anodic peak potential by 68 mV. Kinetic properties of the electrochemical process were also obtained: the number of transfer electrons(n) is 2 and the electron transfer coefficient(α) is 0.48. The peak currents of differential pulse voltammetry of dopamine are linear in the ranges of 5.0×10-7~1.0×10-4 mol/L with a detection limit of 1.0×10-7 mol/L at the signal-to-noise of 3. Relative standard deviation(RSD) is 3.42% for eight parallel detections of 1.0×10-5 mol/L dopamine. The recoveries of this proposed method for determination of dopamine hydrochloride injection solutions are in the range of 94.83%~104.5%.

Key words: Zinc oxide nanorods, intercalated-modification, dopamine, graphite electrode, electrocatalysis