采用电沉积技术将金沉积在铅笔芯电极(PGE)上,借助Au -S作用,将L-半胱氨酸(L-Cys)组装于金表面,利用吖啶橙(AO)与L-半胱氨酸之间的静电作用,将吖啶橙间接组装于金表面,构建成三层自组装膜电极AO/L-Cys/Au/PGE.将该复合膜电极连接在电化学工作站的工作电极和辅助电极端之间,与参比电极浸入溶液中,构建了一个新的检测回路.采用电化学阻抗谱技术和循环伏安法对多层自组装膜的组装过程进行表征.利用吖啶橙与牛血清白蛋白(BSA)间的相互作用,采用零流电位法,通过对比加入不同浓度BSA后零流电位值的变化(△Fzcp)对BSA进行检测.结果显示,在1.0×10-9～1.0×10 -5mol/L范围内,△Ezcp与BSA浓度的对数值呈良好线性,相关系数(r)为0.9970,检出限为1.41×10-11 mol/L.该方法选择性和重复性好,有望应用于其它蛋白的测定.%An electro-deposition method was adopted to prepare gold-capped pencil graphite surface using pencil graphite electrode(PGE). By chemical bonding of Au -S, Z,-cysteine( L-Cys) can be stably immobilized onto the surface of gold, followed by an assembling with acridine orange(AO) via the electrostatic interaction between AO and L-cysteine to obtain an AO/L-Cys/Au/PGE multilayer membrane. The prepared multilayer membrane was connected between the terminal joints of the working electrode and the counter electrode, together with a reference electrode, to construct a novel system. The whole multilayer membrane fabrication process was characterized by cyclic voltammetry and electrochemical impedance spectroscopy. The interaction of AO and the subsequent introduction of bovine serum albumin (BSA) resulted in a significant change of zero current potential (ΔEzep) utilizing zero current potentiometry, thus the electrochemical quantification of BSA could thus be realized. The results showed that ΔEzep and logarithmic of BSA concentration was linear in a wide concentration range of 1. 0 ×10-9 - 1. 0×10-5 mol/L(r =0. 997 0) , and the detection limit was 1. 41×10-11 mol/L. The multilayer membrane exhibited good selectively and reproducibility, and was applicable for the determiantion of other proteins.
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