L-色氨酸分子印迹传感器敏感膜的制备与性能

以L-色氨酸(L-Trp)为模板分子, 邻苯二胺(o-PD)为功能单体, 在金电极表面原位合成了分子印迹聚合物敏感膜; 通过循环伏安法(CV)、 差示脉冲伏安法(DPV)和电化学阻抗谱法(EIS)考察了该电极的性能. DPV测试结果表明, 在1×10^-8~2×10^-7 mol/L范围内, 峰电流与L-Trp的浓度呈线性关系, 检出限为0.3×10^-8 mol/L; 选择识别性实验结果表明, L-Trp印迹敏感膜的印迹因子达到3.72, 相对于干扰物的选择因子均大于1, 对与L-Trp结构相似的L-酪氨酸(L-Tyr)的选择因子也达到2.30, 说明该印迹膜对L-Trp具有良好的选择性; 识别过程动力学研究结果表明, 印迹膜对L-Trp的识别是一个两步连续发生的过程, 即快结合过程和慢吸附过程.

Preparation and Performance of Sensing Films of Molecularly Imprinted Electrochemical Sensor for L-tryptophan

Using L-tryptophan(L-Trp) as template molecule and o-phenylenedia mine as functional monomer, the sensitive molecularly imprinted polymer films was prepared on the surface of gold electrode by in-situ polymerization. The performance of the imprinted electrode was characterized by cyclic voltammetry(CV), differential pulse voltammetry(DPV) and electro-chemical impedance spectroscopy(EIS). A linear relationship between oxidation peak current and concentration of L-Trp was obtained over a range from 1×10-8 to 2×10-7 mol/L with a detection limit of 0.3×10-8 mol/L. From the selectivity experiments, the imprinting factor of L-Trp imprinted film was 3.72 and the selectivity factors of L-Trp compared to interferents were all larger than 1. Although a minor interference was generated by L-Tyr for its structure similar to L-Trp, the selectivity factor also reached 2.30. The results indicated that the imprinted polymer films had a good selectivity for L-Trp. The kinetics of recognition revealed a two-step process of the imprinted polymer films adsorbing L-Trp, which contains a fast binding process and a slow adsorption process.