基于增强电子传递效应的沙蚕毒素类杀虫剂电化学传感研究

Electrochemical sensing of nereistoxin-related insecticides based on the electronic transfer enhancement effect

该文以沙蚕毒素(Nereistoxin,NRT)与铁氰根离子(Fe[(CN)_(6)]^(3-/4-))的静电引力作用为基础,构建了一种简单、快速、廉价、灵敏的检测沙蚕毒素类杀虫剂的电化学传感器。沙蚕毒素类杀虫剂在水解及还原的条件下能够转化为含有两个巯基(-SH)及叔铵结构的NRT。利用-SH与纳米金(AuNPs)的共价键合作用,可将NRT组装到AuNPs修饰的电极表面。由于NRT中质子化的叔铵结构对电子媒介体Fe[(CN)_(6)]^(3-/4-)的静电吸引作用,使Fe[(CN)_(6)]^(3-/4-)靠近电极表面,从而在低离子浓度的条件下产生明显的电化学响应信号。根据电化学响应信号可实现对沙蚕毒素类杀虫剂的高灵敏检测。以检测杀虫磺(Bensultap,BST)为例,该方法在0.001~100μg/L范围内,具有良好的线性响应,检测限为0.3 ng/L。此外,该电化学传感器还具有良好的选择性及重现性,并且能够初步应用于果蔬样品中的杀虫磺的检测。

In this paper,an electrochemical sensor was constructed based on the electrostatic interaction between nereistoxin(NRT) and Fe[(CN)_6]~(3-/4-)for simple,rapid,cost effective and sensitive detection of nereistoxin(NRT)-related insecticides.NRT-related insecticides could convert into NRT that containing two sulfhydryl groups and a tertiary amino group through hydrolysis and reduction process.NRT could be assembled on the surface of gold nanoparticles(AuNPs) modified electrode via Au-S covalent bonding.Because of the electrostatic interaction between the protonated tertiary amino group of NRT and the anionic Fe[(CN)_6]~(3-/4-),the Fe[(CN)_6]~(3-/4-)could close to the electrode surface,producing obvious electrochemical response signal under the low ion concentration condition.According to the electrochemical response signal,the highly sensitive detection of NRT-related insecticides can be realized.Taking the detection of bensultap(BST) as an example,the proposed method has good linear response in the range of 0.001~100 μg/L,and the detection limit was 0.3 ng/L.This strategy also demonstrates good selectivity,reproducibility and the applicability of BST detection in agricultural products.