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目的建立了一种地表水中34种农药残留的分散液液微萃取-保留时间锁定-气相色谱质谱联用快速筛查及定量方法。方法通过分散液液微萃取(DLLME)提取水中的农药残留,对DLLME萃取相关的影响因素如萃取溶剂种类与体积,分散溶剂种类及体积,盐的浓度等进行了优化。最终优化的萃取条件如下:35μl四氯化碳与1 ml丙酮混匀后作为萃取溶剂,通过注射器迅速注射入5 ml水样中,经过离心获得25μl沉积相,吸取其中20μl与1μl环氧七氯内标溶液混合后用保留时间锁定气相色谱-质谱法(RTL-GC-MS)测定。结果通过三个水平六平行的加标回收实验,方法的回收率范围为50%～148%,相对标准偏差(RSD)为4.7%～50%,富集因子为101倍～297倍,方法的检出限(LOD)范围为0.002μg/L～0.065μg/L,定量限(LOQ)为0.007μg/L～0.217μg/L。结论本方法是一种快速,准确,高灵敏度的微萃取方法,能够应用于地表水中多农药监测。
Objective To establish a rapid screening and quantification method for 34 pesticide residues in surface water by liquid-liquid-liquid-liquid microextraction-retention time-locked mass spectrometry. Methods The pesticide residues in water were extracted by liquid-liquid microextraction (DLLME), and the influencing factors of DLLME extraction, such as the type and volume of extraction solvent, the type and volume of solvent, the concentration of salt and so on, were optimized. The final optimization of the extraction conditions are as follows: 35μl carbon tetrachloride and 1 ml of acetone as an extraction solvent after mixing, rapid injection by syringe into 5 ml of water samples, centrifuged to obtain 25μl sedimentary phase, draw 20μl and 1μl of epoxy heptachlor Internal standard solutions were mixed and determined by retention time locked gas chromatography-mass spectrometry (RTL-GC-MS). The results were tested by three horizontal and six parallel spike recoveries. The recoveries were in the range of 50% -148% with relative standard deviations (RSDs) of 4.7% -50% and enrichment factors of 101- 297 times. The limit of detection (LOD) ranged from 0.002μg / L to 0.065μg / L, and the limit of quantification (LOQ) ranged from 0.007μg / L to 0.217μg / L. Conclusion This method is a rapid, accurate and sensitive microextraction method that can be applied to the monitoring of multi-pesticides in surface water.