Supramolecular solvent for the vortex-assisted dispersive liquid–liquid microextraction of aristolochic acids from Aristolochia debilis prior to HPLC-DAD

Abstract

In this study, a new vortex-assisted dispersive liquid–liquid microextraction technique based on supramolecular solvent (SUPRAS) was proposed for the simultaneous extraction and preconcentration of aristolochic acids (AAs) in Aristolochia debilis followed by HPLC-DAD. A new type of SUPRAS, based on hexafluoroisopropanol (HFIP) and primary amine, with a higher density than water was prepared for the first time. HFIP acted as the coacervation agent and density modifier for the preparation of SUPRAS, and only a small amount of HFIP was required to form the SUPRAS. The influencing parameters such as the type and content of primary amine, the content of HFIP, vortex time, solution pH and ionic strength were thoroughly investigated and optimized. The prepared SUPRAS can effectively exclude macromolecules such as starch and be used to extract AAs from herbal medicines with high extraction efficiency. Under the optimized conditions, the method provided satisfactory linearity (1 ∼ 1000 ng mL−1 for AAb and 10 ∼ 1000 ng mL−1 for AAa with determination coefficients higher than 0.9981), low limits of detection (0.3 ∼ 3.1 ng mL−1) and limits of quantification (1.0 ∼ 9.5 ng mL−1). In addition, the intra-day and inter-day precision with relative standard deviations (RSDs%) below 6.8 % were obtained. Finally, the proposed method was applied to determine the AAs in Aristolochia debilis, the extraction recoveries were between 92.8 %∼100.6 % with RSDs% between 0.5 % and 7.2 %. Therefore, the developed method was an easy, efficient and reliable method for determining AAs in Aristolochia herbal materials.