论文部分内容阅读
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 combine the hollow fiber membrane liquid-phase microextraction (HF-LPME) with gas chromatography-electron capture detection (GC-ECD) technology to establish a new method for the determination of pentachloronitrobenzene pesticide residues in gastrodia elata with high sensitivity. Methods: The experimental conditions affecting the extraction enrichment efficiency were optimized. Polypropylene hollow fiber membrane was used, with n-octanol as extraction solvent, extraction solvent volume 20 μL, extraction temperature 30°C, extraction time 30 min, stirring rate 500 r.min-1, and 2.0 μL organic solvent directly after injection to perform gas phase extraction Chromatographic separation detection. DB-1701 elastic quartz capillary column (30m × 0.32mm × 0.25μm) was used. The temperature was increased by program, inlet temperature: 220°C, ECD detector temperature was 250°C, carrier gas, and nitrogen. Results: The enrichment factor for pentachloronitrobenzene was 125 times. The mass concentration of pentachloronitrobenzene was in the range of 2～60 ng.L-1, and there was a good linear relationship with the peak area. The correlation coefficient was greater than 0.99. The detection limit (S/N=3) was 1 ng.L-1. The average recoveries in the actual samples ranged from 90.3% to 97.2% with relative standard deviations of 2.5% to 6.1%. Conclusion: This method is sensitive, simple and suitable for the detection of pesticide residues in Chinese herbal medicines.