吲哚乙酸分子印迹电化学传感器的制备及分析应用

Electrochemical Sensor for Indole Acetic Acid Based on Molecularly Imprinted Polymers Preparation and Application

应用分子印迹技术,以吲哚乙酸为模板分子,吡咯为聚合单体,采用电聚合法在玻碳电极表面合成了性能稳定的吲哚乙酸分子印迹聚合物膜。利用方波伏安法分析吲哚乙酸在该印迹电极上的电化学行为,结果表明:0.55 V(vs.SCE)处的峰电流与浓度为5.0×10-6～2.4×10-4mol/L的吲哚乙酸呈线性关系,检出限(S/N=3)为2.0×10-6mol/L,响应时间为90 s;同一支印迹电极对吲哚乙酸响应值的RSD为1.7%(n=9);该印迹电极对吲哚乙酸具有较好的选择性,相对误差小于5%时,20倍的色氨酸、多巴胺和抗坏血酸以及50倍的组氨酸均对吲哚乙酸的测定不产生干扰。用该印迹电极对绿豆芽和黄豆芽进行分析,吲哚乙酸的浓度分别为5.07μmol/L和18.86μmol/L;对黄豆芽样品进行回收率测定,回收率在97%～104%之间。

In the present work, the indole acetic acid （IAA） molecularly imprinted polymers （MIPs） membrane on the surface of a glassy carbon electrode was prepared by electropolymerization with IAA as templet and pyrrole as functional monomer. Electrochemical oxidation behaviors of IAA on the MIPs modified electrode have been investigated with square wave vohammetry. With the incubation time of 90 s, the peak currents at oxidation potential of 0.55 V （vs. SCE） recorded with the MIPs sensor were proportional to the concentration of IAA in the range of 5.0×10-6 - 2.4×10-4 mol/L, and the detection limit was 2.0 ×10-6 mol/L （S/N = 3）. By repetitive measurement with the same electrode, the RSD （n = 9） of I. 7% showed good repeatability. The MIPs sensor displayed specific selectivity. At relative error less than 5%, tryptophan, dopamine, ascorbic acid and histidine they were 20, 20, 20 and 50 times the concentration of IAA, respectively they did not interfere with IAA determination. The MIPs sensor has been applied to real sample with the results being 5.07 μmol/L and 18.86/xmol/L respectively for soybeam spront and mungbean, and the average recoveries were between 97.1% and 104%.