纳米金修饰玻碳电极在抗坏血酸共存下选择性测定多巴胺

Nanogold-modified Glassy Carbon Electrode for Selective Detection of Dopamine in the Presence of Ascorbic Acid

利用电沉积的方式制备了纳米金 ( Nano- gold,NG)修饰玻碳电极 ( GCE)。该电极对多巴胺 ( DA)和抗坏血酸 ( AA)均有催化作用 ,且多巴胺在纳米金修饰玻碳电极上有较强的吸附作用。同时研究了磷酸缓冲溶液的 p H值和离子强度对 DA的电化学行为的影响。纳米金修饰玻碳电极在 DA和 AA的混合溶液中的循环伏安图上可观察到两个明显分开的氧化峰 ,峰电位差达到 1 5 0 m V。据此 ,提出了两种利用该电极在抗坏血酸共存下选择性测定多巴胺的方法 ,线性范围分别为 3.0× 1 0 - 6 ～1 .0× 1 0 - 4mol/ L和 1 .2 5× 1 0 - 6 ～ 1 .0× 1 0 - 4mol/ L。

The nanogold modified glassy carbon electrode(NG/GCE),which was prepared by electrodeposition, could not only catalytically oxidize dopamine and ascorbic acid but also accumulate the dopamine. The effect of pH value and concentration of phosphate buffer solution (PBS) on the electrochemical behavior of dopamine was studied. Furthermore, two separating oxidation peaks of dopamine and ascorbic acid could be observed at the nano gold modified glassy carbon electrode in cyclic voltammogram. The difference of their oxidation peaks is about 150 mV. Two methods were proposed for determination of dopamine in the presence of ascorbic acid. The peak current of dopamine was in linear relationship with its concentration in the range of 3.0×10 -6 ～1.0×10 -4 mol/L and 1.25×10 -6 ～1.0×10 -4 mol/L, respectively.