分散液液微萃取-气相色谱-质谱法测定鱼塘水中24种农药

Determination of 24 Pesticides in Fish Pond Water by GC-MS Combined with Dispersive Liquid-Liquid Microextraction

采用分散液液微萃取结合气相色谱-质谱法同时快速测定鱼塘水中24种常见农药。在水样5.00mL中快速加入乙醇1.0mL、四氯乙烯30μL,形成乳浊液,静置5min后,以4 000r·min^(-1)转速离心5min,有机相在VF-5MS毛细管色谱柱上分离,质谱分析中选择电子轰击离子源和选择离子监测模式。24种农药的质量浓度在一定范围内与峰面积呈线性关系,检出限(3S/N)在0.33~7.45μg·L^(-1)之间。加标回收率在72.4%~103%之间,测定值的相对标准偏差(n=6)在1.7%~13%之间。该方法成功应用于鱼塘投毒案件中硫丹α、硫丹β和甲氰菊酯的检测。

A method of GC-MS coupled with dispersive liquid-liquid microextraction（DLLME） was developed for simultaneous and rapid determination of 24 pesticides in fish pond water.1.0 mL of ethanol and 30μL of tetrachloroethylene was rapidly added into 5.00 mL of sample to form emulsion.The mixture was let stand for 5 min,and centrifuged at 4 000 r· min^（-1） for 5 min.The organic phase was separated on a VF-5 MS capillary chromatographic column.EI and SIM were adopted in MS analysis.Linear relationships were found between the peak area and the mass conctentration of 24 pesticieds in definite ranges,with detection limits（3 S/N）in the range0.33-7.45μg·L^（-1）.Recovery rates obtained by standard addition method ranged from 72.4% to 103% and RSDs（n=6）were in the range of 1.7%-13%.The poposed method was successfully applied to the detection of endosulfan-α,endosulfan-βand fenpropathrin in fish pond poisoning cases.