顶空单滴微萃取-气相色谱法快速分析百草油中挥发性成分

Rapid assessment of volatile components in Baicao oils by headspace single drop microextrction coupled with gas chromatography

目的：采用简单快速的顶空单滴微萃取-气相色谱法分析测定百草油中挥发性成分薄荷醇和水杨酸甲酯含量。方法：精密吸取样品的甲醇溶液10μL注入盛有5 mL水的样品瓶中,以1.5μLN,N-二甲基甲酰胺为萃取溶液（含内标苯甲醇）,萃取温度为40℃、萃取时间为5 min,萃取后直接吸回0.5μL进样GC分析检测。采用30 m×0.53 mm PEG毛细管柱,FID检测器,程序升温。结果：薄荷醇、水杨酸甲酯和其他成分的分离度良好,加样回收率在95.4%99.2%,RSD均低于1.9%。薄荷醇和水杨酸甲酯分别在1.2680.5（r=0.999 0）,2.491.59×102mg.L^-1（r=0.999 1）线性关系良好。结论：该方法避免了复杂的样品前处理,操作简单快速,定量准确,且成本低,适用于中药中挥发性成分的含量测定。

A simple,fast GC method based on headspace single drop microextraction（HS-SDME） was used for the determination of menthol and methyl salicylate in Baicao oils.A special sample pretreatment method was performed by adding 10 μL the oil its methanol solution into 5 mL water in a caped 10 mL sample vial,a 1.5 μL microdrop of N,N-dimethylformamide with benzyl alcohol as internal standard was formed on the pinpoint of microsyringe needle,exposing 5 min at extraction temperature of 40 ℃.After extraction,0.5 μL of extract was directely injected into GC for analysis.The determination was carried out on a capillary column（0.53 mm×30 m） with PEG as the stationary phase with FID as the detector.A temperature programm was employed.The excellent separation and detection of the target components was accomplished.The average recoveries varied between 95.4% and 99.2%,and relative standard deviations were less than 1.9%.The calibration curves were linear in the range of 1.26-80.5 mg·L^-1 for menthol（r=0.999 0） and 2.49-1.59×10^2 mg·L^-1 for methyl salicylate（r=0.999 1）,respectively.The proposed method is proved to be simple,fast,accurate and low cost without complicated sample pretreatment.HS-SDME is expected to be widely applied for the analysis of volatile components in traditional Chinese medicines.