GC/MS研究茶叶中拟除虫菊酯类农药残留的提取方法

Study on Extraction of Pyrethroid Pesticide Multi-Residues in Tea by GC/MS

摘要: 针对茶叶中拟除虫菊酯类农药残留的提取方法进行研究，比较了加水浸泡对农残提取的影响。结果表明，加水浸泡的样品农残提取率反而降低，通过对样品净化淋洗剂种类和体积的优化选择，总结出一套简便实用的前处理方法。茶叶不用水浸泡，直接用50 mL V（丙酮）∶V（正己烷） =1∶1的溶液超声提取，提取液过活性炭柱，浓缩后再过Florisil柱，用15 mL V（正己烷）∶V（乙酸乙酯）=2∶1的溶液淋洗，浓缩后用GC/MS法测定。回收率为81%~120%，RSD为2.2%~7.8%，检测限为0.002~0.01 mg•kg^-1。

Abstract: The factors of extracting pyrethroid pesticide multi-residues from tea were studied, especially for the influence of adding water into samples before organic solvents extraction. Results show that higher extracting efficiency is acquired without adding water. A simple and accurate pretreatment for pyrethroids in tea is reached by optimizing the choices and volumes of eluting solvents. The samples without water immersing were extracted by 50 mL of V(hexane)∶V(acetone)=1∶1, followed by cleaning up with columns of activated carbon and Florisil respectively. 15 mL of V(hexane)∶V(ethyl acetate) =2∶1 was employed to elute the Florisil column, then was determined by GC/MS. The recoveries range from 81% to 120%, RSDs are 2.2%-7.8%, and the limits of detection are 0.002-0.01 mg•kg^-1.