Dynamic Ultrasonic Nebulisation Extraction Coupled with Headspace Ionic Liquid-based Single-drop Microextraction for the Analysis of the Essential Oil in Forsythia suspensa

IntroductionIonic liquids have attracted much attention as an extraction solvent instead of traditional organic solvent in single-drop microextraction. However, non-volatile ionic liquids are difficult to couple with gas chromatography. Thus, the following injection system for the determination of organic compounds is described. ObjectiveTo establish an environmentally friendly, simple, and effective extraction method for preparation and analysis of the essential oil from aromatic plants. MethodsThe dynamic ultrasonic nebulisation extraction was coupled with headspace ionic liquid-based single-drop microextraction(UNE-HS/IL/SDME)for the extraction of essential oils from Forsythia suspense fruits. After 13min of extraction for 50mg sample, the extracts in ionic liquid were evaporated rapidly in the gas chromatography injector through a thermal desorption unit (5s). The traditional extraction method was carried out for comparative study. ResultsThe optimum conditions were: 3L of 1-methyl-3-octylimidazolium hexafluorophosphate was selected as the extraction solvent, the sample amount was 50mg, the flow rate of purging gas was 200mL/min, the extraction time was 13min, the injection volume was 2L, and the thermal desorption temperature and time were 240 degrees C and 5s respectively. Comparing with hydrodistillation (HD), the proposed method was environment friendly and efficient. ConclusionThe proposed method is environmentally friendly, time saving, with high efficiency and low consumption. It would extend the application range of the HS/SDME and would be useful especially for aromatic plants analysis. Copyright (c) 2013 John Wiley & Sons, Ltd.