A new ionic liquid–water–organic solvent three phase microextraction for simultaneous preconcentration flavonoids and anthraquinones from traditional Chinese prescription

• Ionic liquid–water–organic solvent three phase microextraction is first introduced.
• Flavonoids and anthraquinones were preconcentrated and determined simultaneously.
• The method avoids the centrifugal operation.
• It is a rapid pretreatment technology for the entire process takes less than 8 min.
• The LOQ of the proposed technique is very low.

A novel technique, ionic liquid–water–organic solvent three phase microextraction (ILWOS-3p-ME) was developed and introduced for simultaneous preconcentration and determination of flavonoids and anthraquinones in Chinese herbal formula and its preparations. This technique was performed in one step by using a syringe. High performance liquid chromatography with an UV-detector (HPLC/UV) was subsequently conducted. Two solvents with different densities (organic solvent and ionic liquid with densities less than and higher than water, respectively) were separately placed in a syringe, which was used as an extraction device. A cloudy emulsion was formed by manually shaking the syringe. The mixture was allowed to stand for several minutes; afterward, the emulsion readily separated into three phases: an upper organic solvent extraction phase; a middle aqueous sample phase; and a lower ionic liquid extraction phase. Both the upper and lower layers were transferred to a small Eppendorf (EP) tube. Conducting ILWOS-3P-ME with HPLC/UV, we simultaneously determined the bioactive components of flavonoids and anthraquinones in traditional Chinese medicine. ILWOS-3P-ME is a simple, rapid, practical, and effective method to extract and preconcentrate of different types of trace bioactive components from traditional Chinese medicine simultaneously.

(A) Sample solution was placed in a syringe. (B) 100 μL of heptanol and 100 μL of [C6MIM][PF6] were injected separately into the sample solution by a syringe. (C) An emulsion was formed. (D) The phases separated after the mixture was allowed to settle for 3 min. (E) The syringe plunger was pressed upward, and the upper phase was collected in a small EP tube. (F) Turning the syringe downward, the lower phase was collected in the same EP tube by pressing the plunger slightly.Figure optionsDownload as PowerPoint slide