二乙腈基二硫纶自组装膜修饰金电极对多巴胺的电化学催化作用
On the Electrocatalytic Action Toward Dopamine at the Na2mnt-Self-Assembled Monolayer Modified Gold Electrode
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摘要: 将经抛光清洗的金电极置于5 mmol·L-1 cis-1,2-二腈基乙烯-1,2-二硫醇钠(简称二腈基二硫纶,Na2mnt)溶液中浸泡24 h,制得Na2mnt自组装膜修饰的金电极mnt-SAM/Au,用电化学方法研究了上述修饰电极的电化学性质。结果表明:多巴胺在mnt-SAM/Au修饰电极上的氧化还原可逆性显著变好,峰电流增加;此氧化还原过程受扩散控制,多巴胺在电极上无吸附,电极不受污染。由于多巴胺是生物物质,选用在pH 7.00的磷酸盐介质中检测。在所选定的条件下,多巴胺的浓度在4.0×10-6~2.0×10-4mol·L-1之间与其相应的峰电流(i/nA)之间呈线性关系。Abstract: Na2mnt-self-assembled monolayer modified gold electrode (mnt-SAM/Au) was prepared by immersion of the polished and cleaned Au-electrode into solution of 5 mmol·L-1 cis-disodium-1,2-dicyanoethylene-1,2-dithiolate (also named as dicyanodithiolene and abbr. as Na2mnt) for 24 h. Electrochemical behavior of the modified electrode was studied and it was found that the reversibility of the radox of dopamine (DPM) at the mnt-SAM/Au modified electrode was improved significantly; an increase of peak current was observed; the redox process was controlled by diffusion; and no adsorption of DPM and no contamination were found on the modified electrode. As a biomatter of DPM, a buffer medium of PBS with pH 7.00 was chosen for its detection. Under the optimum conditions, linear relationship between values of concentration of DPM in the range of 4.0×10-6-2.0×10-4mol·L-1 and the respective peak current (i/nA) was found.
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