中空纤维膜液相微萃取-气相色谱法测定天麻中五氯硝基苯

Determination of quintozine in gastrodia by hollow fiber-based liquid phase microextraction coupled with gas chromatography

目的:将中空纤维膜液相微萃取(HF-LPME)与气相色谱-电子俘获检测(GC-ECD)技术相结合,建立了高灵敏度测定天麻中五氯硝基苯农药残留的新方法。方法:对影响萃取富集效率的实验条件进行优化。采用聚丙烯中空纤维膜,以正辛醇为萃取溶剂,萃取溶剂用量20μL,萃取温度30℃,萃取时间30min,搅拌速率为500r.min-1,萃取后取2.0μL有机溶剂直接进样进行气相色谱分离检测。采用DB-1701弹性石英毛细管柱(30m×0.32mm×0.25μm),程序升温,进样口温度:220℃;ECD检测器温度250℃,载气,氮气。结果:该方法对五氯硝基苯的富集倍数为125倍。五氯硝基苯质量浓度在2～60ng.L-1范围内,与峰面积之间有良好的线性关系,相关系数均大于0.99,检测限(S/N=3)为1ng.L-1,实际样品中的加标回收率为90.3%～97.2%,相对标准偏差为2.5%～6.1%。结论:本方法灵敏、简便,适用于中药材中五氯硝基苯农药残留的检测。

Objective：To develop an analytical method for the determination of quintozine in Gastrodia by hollow fiber-based liquid phase microextraction（HF-LPME）coupled with gas chromatography electron capture detector（GC-ECD）.Method：Some main experimental parameters that afect the extraction efficiency were optimized.20 μL of octanol was selected as both the extraction solvent and the impregnation solvent.The extraction was carried out at 30 ℃ temperature with a stirring rate of 500 r·min-1 for 30 min.After extraction,2.0 μL of octanol was then injected into GC for further analysis.DB-1701 capillary（30 m×0.32 mm×0.25 μm）was adopted.The column temperature rise by programming.Injector temperature was 220 ℃ with ECD temperature of detector at 250 ℃.The carrier gas was nitrogen.Result：Under this conditions,the concentration factors for quintozine were 125.The calibration curve was linear over a range of 2-60 ng·L-1（r0.99）.The limits of detection（LOD）were 1 ng·L-1（S/N=3）for quintozine.The recoveries were 90.3%-97.2% with relative standard deviations（RSD）between 2.5%-6.1%.Conclusion：The method is sensitive,simple and sutiable for determination of quintozine in Gastrodia.