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-SelfAssembled Monolayer Modified Gold Electrode

将经抛光清洗的金电极置于5mmol·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24h,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4.0×10-6~2.0×10-4 mol·L-1之间与其相应的峰电流(i/nA)之间呈线性关系。

Na2mnt-self-assembled monolayer modified gold electrode(mnt-SAM/Au)was prepared by immersion of the polished and cleaned Au-electrode into solution of 5mmol·L-1 cis-disodium-1,2-dicyanoethylene-1,2-dithiolate(also named as dicyanodithiolene and abbr.as Na2mnt)for 24h.Electrochemical behavior of the modified electrode was studied and it was found that the reversibility of the radox of dopamine(DPM)at the mntSAM/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 7.00was chosen for its detection.Under the optimum conditions,linear relationship between values of concentration of DPM in the range of 4.0×10-6-2.0×10-4 mol·L-1 and the respective peak current(i/nA)was found.