基于单(6-巯基-6-去氧)-β-环糊精修饰金电极对L-半胱氨酸的快速灵敏检测

将单(6-巯基-6-去氧)-β-环糊精(HS-β-CD)通过金硫键自组装在金电极(GE)表面, 构建了一种简单、 快速、 灵敏的超分子识别L-半胱氨酸(L-Cys)的电位型电化学传感器. 通过循环伏安法和交流阻抗法研究了膜表面的电化学行为; 通过扫描电子显微镜(SEM)和X射线光电子能谱(XPS)表征了电极表面的膜组装效果, 其作用机制是固定在金电极表面的HS-β-CD空穴可通过分子间作用力吸附结合带负电的L-Cys, 使电极表面的膜电位发生改变, 导致对L-Cys的超分子选择性识别作用, 从而实现对L-Cys的定量分析. 在优化的实验条件下, 该电极在pH=6.0的磷酸盐缓冲溶液中对L-Cys有良好的电位响应性能, 线性范围为1.0×10 ^-7~1.0×10 ^-4 mol/L, 斜率为(-65.29±1.0) mV/pc(25 ℃), 检测下限达到6.0×10 ^-8 mol/L; 电极响应速度快、 稳定性和重现性好、 抗干扰能力强. 将该电极用于实际猪血清和猪尿液样品中L-Cys含量的测定, 回收率为95.0%~104.7%, 表明该新型电极在生命科学等领域具有良好的应用前景.

Rapid and Sensitive Detection of L-Cysteine Based on Mono( 6-mercapto-6-deoxy)-β-cyclodextrin Modified Gold Electrode

A simple,rapid and sensitive L-cysteine( L-Cys) potentiometric electrochemical sensor was constructed by using mono( 6-mercapto-6-deoxy)-β-cyclodextrin( HS-β-CD) self-assembled on surface of gold electrode( GE) via gold-sulfur bond. The electrochemical behavior of the electrode membrane surface was investigated through cyclic voltammetry and impedance analysis. Scanning electron microscopy and X-ray photoelectron spectroscopy have also demonstrated the film assembly effectiveness of the electrode. And the interaction mechanism of the electrode was that the cyclodextrin cavity of HS-β-CD immobilized on the gold surface can adsorb and bind electronegative L-Cys through intermolecular force,resulting in change of the membrane potential on the electrode surface and further realization of supramolecular selective recognition of L-Cys. In the optimal condition,the modified electrode had good potential response feature to L-Cys in PBS( pH= 6. 0) with a linear range of 1. 0 × 10^-7-1. 0×10^-4 mol/L and a slope of(-65. 29 ± 1. 0) mV/pc( 25 ℃) . The detection limit can reach 6. 0×10^-8 mol/L. The electrode responded quickly,which had high stability,good reproducibility,and strong anti-interference ability. The electrode can be well used for the determination of L-Cys in actual pig serum and pig urine samples with recovery rate of 95. 0%-104. 7%,showing its important application prospects in life science fields.