固相萃取气相色谱内标法测定桔梗中拟除虫菊酯的农药残留

 目的 本实验建立了桔梗中甲氰菊酯、高效氯氟氰菊酯、溴氰菊酯、氰戊菊酯、氯菊酯、联苯菊酯等 6 种拟除虫菊酯类农药残留的提取、净化及其气相色谱法。 方法 样品运用石油醚提取，乙腈 - 二氯甲烷 (5:95) 洗脱， GC-ECD 检测 , 内标法定量。 结果 6 种拟除虫菊酯农药回收率在 78.86% ～ 97.80% ， RSD 在 1.17% ～ 11.63% ，可以满足农药残留分析的要求。 结论 方法灵敏度高，选择性强，操作简单、快速，净化效果好等特点，可应用于桔梗药材中痕量农药残留的检测。

Determination of Pyrethroid Pesticides in <>Platycodon trandiflorum A.DC. by SPE-GC

OBJECTIVE To develop a SPE-GC method for the extraction,clean-up and determination of fenpropathrin, lambda-cyhalothrin, deltamethrin, fenvalerate,permethrin and bifenthrin in Platycodon grandiflorum A.DC. METHODS The pesticides determination was performed gas chromatography. Pesticide residues were extracted from samples with ligarine.Extracts were cleane-up by CARB/NH2 column, eluted with acetonitrile-chloromethane(5∶95). Analytical screening was determined by gas chromatography with ECD detector, The pyrethroids were quantified by internal standard method. RESULTS The average recoveries and RSD were in the ranges of 78.86%～97.80% and 1.17%～11.63%, respectively.The method met the requirement of pesticide residue analysis. CONCLUSION The proposed method has high sensitivity,repeatability and selectivity,it is simple and fast,which can be used for the analysis of 6 pyrethroid pesticides.