Fe3O4 sphere-assisted microwave distillation coupled with ionic liquid-based HS-SDME followed by GC-MS for the rapid analysis of essential oil in dried lavender
In this work, Fe3O4 sphere-assisted microwave distillation (MD) coupled with ionic liquid-based headspace single-drop microextraction (IL-HS-SDME) followed by GC-MS was developed for the analysis of essential oil in dried lavender. Loose Fe3O4 spheres were used as a microwave absorption medium for dry distillation of dried lavender. A home microwave oven without any modification was used in the MD-IL-HS-SDME. The effects of the experimental parameters were investigated. The optimal analytical conditions were: extraction solvent of [C6mim]BF4, single-drop volume of 2 μL, irradiation time of 5 min, extraction time of 20 min, sample amount of 30 mg and the addition of 5 mg Fe3O4 to the sample. The relative standard deviations for determining six representative compounds were in the range from 2.70 to 8.82%. The developed method was successfully applied to analyze 12 samples of three varieties of lavender (French blue, C-197(2) and H-701). A total of 36 compounds were identified by the proposed method. Principal component analysis was used to differentiate lavender varieties and to identify discriminant varietal markers. The results showed that the Fe3O4 sphere-assisted MD-IL-HS-SDME is a fast, sensitive, low cost and small sample consumption method for the determination of the essential oil in dried plant materials.