基于磁性自组装分子印迹传感器测定赤霉素A3

Determination of Trace Gibberellin A3 by Magnetic Self-assembly Molecularly Imprinted Electrochemical Sensor

利用共沉淀法合成了磁性Fe3O4纳米粒子,进一步表面功能化,合成Fe3O4@Au磁性纳米粒子提高粒子表面的亲和性。在高亲和力的金壳表面自组装L-半胱氨酸-GA3,将其滴涂在磁控玻碳电极表面,电聚合L-半胱氨酸制得对GA3具有特异性识别能力的MIP/Fe3O4@Au修饰电极。对Fe3O4@Au磁性纳米粒子的表面形态及粒度分布进行了透射电镜分析,对GA3,MIP及nMIP的结构及成分进行了红外光谱对比分析。利用电化学方法对测试体系的工作条件进行了优化。研究表明,当电聚合圈数为30圈,以乙酸-甲醇（1：8,V/V）作为洗脱液、洗脱时间为5min、重吸附时间为7min时,传感器具有较高的稳定性,且对GA3具有较好的识别效果。结果表明,探针离子K3[Fe（CN）6]/K4[Fe（CN）6]的氧化峰电流值与GA3浓度在1.0×10^-11-1.0×10^-8mol/L范围内呈线性关系,检出限为2.6×10^-12mol/L。此传感器已应用于啤酒中GA3的检测。

The magnetic Fe3O4 nanoparticles were synthesized by co-precipitation method,and then magnetic Fe3 O4@Au nanoparticle was synthesized to improve the affinity of particle surface. L-Cys-GA3 was grafted on the surface of gold clad by self-assembly method, and then dropped it on glassy carbon electrode, for further manufacture of MIP/Fe3 O4@Au by using electropolymerzation L-Cys. The surface morphology and particle size distribution of Fe3 O4@Au were studied by TEM. The structure and composition of gibberellins A3, MIP and nMIP were studied by IR. The test system was optimized, and the results showed that when the cycles of electropolymerization was 30, acetic acid：methanol （1：8, V/V） was chosen as eluent, elution time was optimized for 5 min and rebinding time for 7 min, the sensor got a high stability and good recognition ability for gibberellins A3 . The concentration of gibberellins A3 in the range of 1 . 0 × 10^-11-1 . 0 × 10^-8 mol/L had a relationship with the oxidation peak current of probe, with the detection limit of 2. 57×10^-12 mol/L. The sensor was successfully used for the determination of GA3 in beer sample.