Novel multiple-solvent simultaneous microextraction for flavonoid and anthraquinone preconcentration in traditional Chinese medicine

Abstract

In this study, a novel multiple-solvent simultaneous microextraction (MSSME) method is presented and introduced to preconcentrate flavonoids and anthraquinones from traditional Chinese medicines simultaneously. This technique was performed in one step by using two different solvents (immiscible with each other) carried by two filter membranes (1 cm × 1 cm), which were used as extraction devices. High-performance liquid chromatography with ultraviolet detection (HPLC/UV) was subsequently conducted. The wide exchange surface and multiple solvents respective extraction provided by the filter membrane showed that the proposed technique could be potentially applied as a sample pretreatment technology. The variables influencing MSSME, such as types of extraction solvents, filter membrane area (or volumes of extraction solvents), aqueous phase pH, ionic strength, extraction stirring rate, extraction time, and sample volume were investigated and optimized. Under optimized conditions, the enrichment factors of the analytes were 68 to 132 and the limits of detection were <0.96 ng mL⁻¹. In addition, satisfactory recoveries of 80.1% to 119.2% and precisions of 2.2% to 8.8% were achieved. These results show that MSSME coupled with HPLC/UV is a simple, rapid, practical, and effective method to extract and preconcentrate different types of trace components from complex samples simultaneously.