分子印迹电化学传感器对动物源性食品中氯霉素残留检测方法的建立与应用

宋心怡; 韩中惠; 赵晓磊; 何金兴

doi:10.13386/j.issn1002-0306.2023020124

分子印迹电化学传感器对动物源性食品中氯霉素残留检测方法的建立与应用

Establishment and Application of Molecularly Imprinted Electrochemical Sensors for the Detection of Chloramphenicol Residues in Foods of Animal Origin

摘要

摘要: 实验将分子印迹技术与电化学工作站结合，利用多壁碳纳米管与金、铂纳米粒子对电极进行双敏化处理，用以增强玻碳电极表面电子转移速率，增强电化学传感器电流响应值，从而降低检测限。采用扫描电镜和电化学手段进行表征；通过吸附动力学试验与等温吸附试验对分子印迹修饰的电极进行研究，确定吸附性能，并对其选择性进行分析；以修饰后的电极检测实际样品鸡肉、鱼肉和牛奶中的氯霉素，分析其检测效果。结果表明，修饰后的电极表面具有杂乱的多壁碳纳米管状结构，从电化学循环伏安法（cyclic voltammetry，CV）、电化学阻抗谱（electrochemical impedance spectroscopy，EIS）可以清楚地看出电极的修饰效果，多壁碳纳米管与金、铂纳米粒子对电极表面电子传导速率的增强效果明显。分子印迹修饰对其结构类似物具有良好的选择性；传感器在氯霉素浓度为0.66~56.66 µg/L之间呈现出良好的线性关系，R²>0.99，检出限为0.45 nmol/L（0.146 µg/L）。在对实际样品鸡肉、鱼肉和牛奶的检测中，氯霉素的回收率分别为83.72%~103.43%，相对标准偏差（RSD）为2.61%~6.03%，该结果满足GB/T 27404-2008定量分析检测要求（被测组分<0.1 mg/kg，回收率范围为60%~120%），且试验方法具有极低的检测限。

Abstract: A novel electrochemical sensor was fabricated for the rapid and sensitive detection of chloramphenicol (CAP). The experiments combined molecular imprinting technology with electrochemical workstation, using multi-walled carbon nanotubes (MWCNTs) and gold-platinum nanoparticles to double sensitize the electrode, which was used to enhance the electron transfer rate on the surface of the glassy carbon electrode (GCE) and enhance the current response value of the electrochemical sensor, thus reducing the detection limit. Characterization was carried out using scanning electron microscopy and electrochemical methods. Study the adsorption performance of molecularly imprinted modified electrodes through adsorption kinetics experiments and isothermal adsorption experiments, and analyze their selectivity. Detect chloramphenicol in actual samples of chicken, fish, and milk using modified electrodes and analyze their detection effectiveness. Results showed that, the modification effect of the electrode could be clearly seen from the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), and the enhancement of the electron conduction rate on the electrode surface by MWCNTs and gold-platinum nanoparticles (Au-PtNPs) was obvious. The adsorption properties of the molecularly imprinted modified electrodes were studied by adsorption kinetic tests and isothermal adsorption tests to determine the adsorption properties and analyze their selectivity. The experiments showed good selectivity for its structural analogues, and the analyticity of the sensor was evaluated, and the sensor showed good linearity between CAP concentrations of 0.66 and 56.66 µg/L with R²>0.99 and a detection limit of 0.45 nmol/L (0.146 µg/L). The recoveries of CAP were 83.72%~103.43% with the relative standard deviations (RSDs) of 2.61%~6.03% in the assays of actual samples of chicken, fish and milk, respectively, which met the requirements of GB/T 27404-2008 for quantitative analysis and detection (the measured components were <0.1 mg/kg and the recoveries ranged from 60% to 120%). Compared with other literature methods, the test method has extremely low detection limits.