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目的采用密度小于水的轻质溶剂为萃取剂并结合溶剂去乳化技术,建立溶剂去乳化-分散液相微萃取技术-气相色谱质谱联用测定水样中8种有机氯农药的方法。方法以环己烷为萃取剂,将其与分散剂丙酮混合后,快速注入水样中,获得乳化体系;然后加入丙酮作为去乳化剂破坏乳化体系,无须离心使两相分层;取上层有机相(环己烷)进行GC-MS分析。结果考察了萃取剂、分散剂、去乳化剂的种类和体积、盐浓度、p H值等对萃取效率的影响。工作曲线在0.050μg/L~2.0μg/L浓度范围内有良好的线性关系,有机氯农药的检出限为0.032μg/L~0.047μg/L。方法加标回收率为93.0%~102%,相对标准偏差为2.37%~4.86%。结论本方法快速灵敏,有机溶剂消耗少,对环境友好,不仅适用于水中有机氯农药批量分析,也为实现其样品处理的自动化提供了技术和方法学支持。
OBJECTIVE To establish a method for the determination of eight organochlorine pesticides in water samples by gas chromatography-mass spectrometry combined with solvent de-emulsification using light solvent with lower density than water as extractant and solvent de-emulsification technology. Methods Cyclohexane was used as extractant, which was mixed with dispersant acetone and quickly injected into water sample to obtain emulsified system. Acetone was then used as de-emulsifier to destroy the emulsified system, and the two phases were separated without centrifugation. The upper organic layer Phase (cyclohexane) was subjected to GC-MS analysis. Results The effects of extractant, dispersant, type and volume of de-emulsifying agent, salt concentration and p H value on extraction efficiency were investigated. The working curve has a good linearity in the range of 0.050μg / L ~ 2.0μg / L, and the detection limit of organochlorine pesticides is 0.032μg / L ~ 0.047μg / L. The recoveries of the methods were 93.0% ~ 102% with relative standard deviations of 2.37% ~ 4.86%. Conclusion The method is rapid, sensitive, has low consumption of organic solvents and is environmentally friendly. It is not only suitable for batch analysis of organochlorine pesticides in water, but also provides technical and methodological support for the automation of sample handling.