Utilizing ionic liquid-dispersive liquid-liquid microextraction coupled with HPLC for the determination of anthraquinones in Folium Sennae

The European Union (EU) modified a maximum residue limit of 0.02 mg. kg- 1 for Anthraquinones (AQs) in imported black tea from China, India, and SriLanka in 2015 due to food safety concerns. Nevertheless, existing methods including high-performance liquid chromatography (HPLC), thin-layer chromatography scanning, and spectrophotometry have not yet met the required sensitivity thresholds. In this study, a dispersive liquid-liquid microextraction method was developed to determine four AQs in Folium Sennae that potentially offering an alternative to solid-phase microextraction. By optimization analysis, the optimal extraction conditions were determined as follows: 50 mu L [BeMim][Tf2N] ionic liquid was used as the extractant, 700 mu L methanol was used as the dispersant, and ultrasonic extraction was carried out for 6 min under the condition of pH 4. The LOD and LOQ of the four anthraquinone monomers were 4.1-8.2 mu g center dot L-1 and 1.6-3.4 mu g center dot L-1, respectively, with good linear relationships (R2 = 0.999) under optimal conditions. When this method was used to analyze anthraquinone compounds in Folium Sennae from different regions (China, India; Indonesia), the recovery rates ranged from 92.1 % to 99.8 %, suggesting remarkable application potential. Overall, the Ionic liquids-based dispersion liquid- liquid microextraction coupled with high-performance liquid chromatography (IL-DLLME-HPLC) method characterized by excellent sensitivity, better facility, and steady repeatability, was developed for the determination of AQs. This method plays a crucial role in ensuring the safety of Folium Sennae by achieving the required limits and provides insights into the safety evaluation of herbal medicines.