title: Dynamic ultrasonic nebulisation extraction coupled with headspace ionic liquid-based single-drop microextraction for the analysis of the essential oil in Forsythia suspensa.
abstract: BACKGROUND
  Ionic 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.
  
  
  OBJECTIVE
  To establish an environmentally friendly, simple, and effective extraction method for preparation and analysis of the essential oil from aromatic plants.
  
  
  METHODS
  The 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 13 min of extraction for 50 mg sample, the extracts in ionic liquid were evaporated rapidly in the gas chromatography injector through a thermal desorption unit (5 s). The traditional extraction method was carried out for comparative study.
  
  
  RESULTS
  The optimum conditions were: 3 μL of 1-methyl-3-octylimidazolium hexafluorophosphate was selected as the extraction solvent, the sample amount was 50 mg, the flow rate of purging gas was 200 mL/min, the extraction time was 13 min, the injection volume was 2 μL, and the thermal desorption temperature and time were 240 °C and 5 s respectively. Comparing with hydrodistillation (HD), the proposed method was environment friendly and efficient.
  
  
  CONCLUSIONS
  The 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.
authors.affiliation: Department of Chemistry, Jilin University, Changchun, 130012, P.R. China.
authors.forename: Jinjuan
authors.initials: J
authors.lastname: Yang
authors.forename: Hongmin
authors.initials: H
authors.lastname: Wei
authors.forename: Xiane
authors.initials: X
authors.lastname: Teng
authors.forename: Hanqi
authors.initials: H
authors.lastname: Zhang
authors.forename: Yuhua
authors.initials: Y
authors.lastname: Shi
mesh_terms: D031657:Forsythia / Q000737:chemistry*; D005638:Fruit / Q000737:chemistry; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D007093:Imidazoles; D052578:Ionic Liquids; D059627:Liquid Phase Microextraction / Q000379:methods*; D009795:Octanes; D009822:Oils, Volatile / Q000032:analysis / Q000302:isolation & purification*; D012997:Solvents; D013696:Temperature; D013997:Time Factors; D014465:Ultrasonics; D014835:Volatilization
chemical_list: C559458:1-methyl-3-octylimidazolium hexafluorophosphate; D007093:Imidazoles; D052578:Ionic Liquids; D009795:Octanes; D009822:Oils, Volatile; D012997:Solvents
keywords: Forsythia suspensa; Headspace single-drop; ionic liquid; microextraction; ultrasonic nebulisation extraction