人血清中半胱氨酸测定用自组装电化学传感器的研制

Fabrication of the Electrochemical Biosensor for the Determination of Homocysteine in Human Serum by Self-assembly Technique

将四羧基钌（Ⅱ）酞菁（RuPc）共价键合到自组装在Au电极表面的巯基丁二胺单分子层上，获得了自组装修饰电极（RuPc-CME）。研究了它的电化学性质，并采用扫描电子显微镜（SEM）、傅立叶变换红外光谱（FT-IR）、x射线光电子能仪（XPS）以及循环伏安法（CV）对该电极表面进行了表征。在pH5.5时，循环伏安图显示RuPc修饰层存在一对氧化还原峰，其峰电位分别为V^1pa=1．12V，V^1pc=1．09V（vs．SCE）。它的表面电子的电荷转移系数仅为0．52，速率常数K=1.43s^-1，表面覆盖度Г=7.82×10^-10mol／cm^2，属于单分子层吸附。在pH3．0-5．5的PBS底液中，该电极对L-半胱氨酸（Hcy）的氧化有催化作用，采用计时安培电流法（CA）测定催化电流与Hcy的浓度在5.0×10^-7-5．4×10^-5mol／L范围内呈良好的线性关系，检出限为1.8×10^-7mol／L。用于检测人血清样品中的Hcy，结果满意。

A novel electrochemical biosensor based on the formation of one monolayer containing thiol- tailed groups was fabricated through the covalent binding of Ru phthlocyanine（RuPc） on a dimercapto- succinic diamine-modified gold electrode by using the self-assembly technique. A pair of redox peaks （ V^1pa= 1.12 V,V^1pc = 1.09 V vs. SCE） was shown in the PBS buffer（pH 5.5）, The electrode surface has been characterized by SEM, FT-IR, XPS and cyclic vohammetry（CV）. The charge transfer constant （α） was found 0.52, and the rate constant（Ks） is 1.43s^-1, The average surface coverage of CuACYS was 7.82×10^-10mol/cm^2, showing its monolayer modified. This CME electrode shows an excellent electrocatalytic activity for the oxidation of homocysteine（Hcy） in PBS buffer between pH 3, 0 to 5, 5, The peak currents of chronoamperometry（CA） is linear with Hcy concentrations in the range of 5.0×10^-7 -5.4×10^-5 mol/L and the detection limit was 1.8×10^-7 mol/L. It has been employed for the determination of Hcy in human serums with good results.