叶类蔬菜有机氯农药残留测定过程中的提取和净化

EXTRACTION SOLVENT AND SOLID-PHASE MATERIAL IN DETERMINATION ORGANOCHLORINE PESTICIDES IN LEAF VEGETABLES

用柱萃取法提取 ,气相色谱 电子捕获检测器 (GC ECD)测定蔬菜中的多种有机氯农药 .比较了不同提取溶剂对蔬菜中有机氯农药的提取效率 .就回收率而言 ,正己烷和丙酮 (V/V ,4∶1 ) >石油醚和丙酮 (V/V ,4∶1 ) >二氯甲烷和丙酮 (V/V ,4∶1 ) >纯正己烷 .用正己烷和丙酮作提取溶剂时 ,1 2种有机氯农药中有 1 0种的回收率在 80 %以上 ,变异系数在 1 %— 1 5 %之间 .不同固相萃取 (SPE)填料对有机氯农药的纯化效率为 :硅胶对目标物质的净化效率要高于硅藻土和氟罗里硅土 ,硅胶做填料时变异系数在 1 5 %以下 .因此 ,本实验认为用正己烷和丙酮 (V/V ,4∶1 )做提取剂、选择硅胶做填料能够对蔬菜中多种有机氯农药有较好的提取和净化效果 ,是一种较理想的蔬菜中有机氯农药的分析方法 .

Residues of organochlorine pesticides in vegetables were extracted by using column extraction method and analyzed by gas chromatography equipped with a 63 Ni electron-capture detector(GC-ECD)system.The extraction efficiency of different solvents and purification efficiency of different soild-phase materials in SPE column were compared in the experiment.The results showed that,the recoveries of different extraction solvents ranked in following order:hexane/acetone(V/V, 4∶1 )>petroleum ether/acetone(V/V,4∶1)>dichloromethane/acetone(V/V,4∶1)>hexane.Hexane/acetone as extraction solvent had the highest extraction efficiency,10 organochlorine pesticides obtained the recoveries higher than 80% and relative standard deviation ranging from 1% to 15%.Silica gel as cleaning-up material had significantly higher efficiency than Celite and Florisil,and relative standard deviation less than 15%.