构建ZIF-67@MWCNTs修饰玻碳电极检测葛根中的杀螟硫磷

Detection of fenitrothion in Radix Puerariae by ZIF-67@MWCNTs modified glassy carbon electrode

目的构建ZIF-67@MWCNTs修饰玻碳电极(GCE)用于检测葛根中的杀螟硫磷(fenitrothion,FNT)。方法合成ZIF-67@MWCNTs,经超声分散后,将ZIF-67@MWCNTs分散液滴涂在GCE上,得到GCE/ZIF-67@MWCNTs修饰电极,采用循环伏安法(CV)、化学阻抗谱(EIS)、差分脉冲伏安法(DPV)考察FNT在GCE/ZIF-67@MWCNTs上的电化学行为。对不同材料修饰的电极进行电化学检测,以及对滴涂量、缓冲液的pH进行优化。结果在滴涂量为5μL、缓冲液pH=6.5的最适条件下,FNT的线性范围为0.02~2.0μg/mL,检出限为0.013μg/mL(S/N=3);对GCE/ZIF-67@MWCNTs的重现性、稳定性和抗干扰性进行试验,具有良好的结果。此修饰电极可用于中药葛根中的FNT的含量测定,回收率为94.0%~108%。结论构建的修饰玻碳电极适用于测定实际样品葛根粉中的FNT。

Objective To construct a ZIF-67@MWCNTs-modified glassy carbon electrode(GCE)for detecting fenitrothion(FNT)in Radix Puerariae.Methods ZIF-67@MWCNTs was synthesized and ultrasonically dispersed,followed by drop-coating the dispersion onto a glassy carbon electrode to prepare a GCE/ZIF-67@MWCNTs modified electrode.Cyclic voltammetry(CV),electrochemical impedance spectroscopy(EIS)and differential pulse voltammetry(DPV)were used to investigate the electrochemical behavior of FNT on the modified electrode.The electrochemical performance of electrodes modified with different materials,as well as the optimization of drop-coating volume and buffer solution pH,were evaluated.Results Under the optimal conditions of a 5μL drop-coating volume and buffer pH of 6.5,the linear detection range for FNT was 0.02 to 2.0μg/mL,with a detection limit of 0.013μg/mL(S/N=3).Reproducibility,stability and anti-interference experiments demonstrated good performance of the GCE/ZIF-67@MWCNTs electrode.The modified electrode was successfully applied to determine the FNT content in Radix Puerariae,achieving a recovery rate of 94.0%to 108%.Conclusion The constructed modified glassy carbon electrode is suitable for determining FNT in real samples of Radix Puerariae powder.