分散液液微萃取-气质联用法测定水样中的菊酯类农药

研究了用分散液液微萃取-气质联用法分析测定水样中的三种拟除虫菊酯类农药残留(联苯菊酯、氯氰菊酯和溴氰菊酯)的方法。通过实验确定了当样品体积为5 mL时的最佳萃取条件为:14μL氯苯作萃取剂,1.0 mL乙腈作分散剂,超声萃取1 min。在最佳实验条件下,该方法对水样中三种拟除虫菊酯类农药的富集倍数在318~363之间;线性范围分别在0.05~50μg/L和0.5~100μg/L之间;最低检出限在0.002~0.04μg/L之间;相对标准偏差RSD(n=6)在3.7%~11.2%之间;加标水样的回收率在86.0%~117.0%之间。

Determination of Pyrethroid Pesticides in Water Samples by Dispersive Liquid-liquid Microextraction Coupled with GC-MS

The application of the dispersive liquid-liquid microextraction combined with the gas chromatography-mass spectrometry on the determination of three pyrethroid pesticides（bifenthrin,cypermethrin and deltamethrin）in water samples was studied.Several parameters of the extraction procedure,such as the type of extraction and dispersive solvents and their volumes,ionic strength,extraction time,and shaking mode,were optimized by experiments.Under optimum conditions（14 μL chlorobenzene as the extraction solvent,1.0 mL acetonitrile as the dispersive solvent,sonication for 1 min）,the enrichment factors of the three pesticides ranged from 318 to 363,and the linearity varied from 0.05~50 μg/L and 0.5~100 μg/L,respectively.The limits of detection（LODs）,based on a signal-to-noise ratio（S/N）of 3,varied from 0.002 to 0.04 μg/L.The relative standard deviations（RSDs）ranged from 3.7% to 11.2%（n=6）.The relative recovery（RR）in the river water and lake water were between 86.0%~117.0%.