A solid-phase extraction method using mixed hemimicelles and high-performance liquid chromatographydiode array detection was proposed for the pre-concentration and determination of anthraquinones (AQs) in Radix et Rhizoma Rhei samples. The mixed hemimicelles were synthesized by coating cetyltrimethylammonium bromide (CTAB) on Fe3O4 nanoparticles. Based on the superparamagnetic character of Fe3O4 nanoparticles, the proposed method had some special advantages, including high surface area, facile dispersion, rapid separation, convenient utilization, and environmental benignity. Some important factors that influence extraction efficiency of AQs, including amounts of Fe3O4 nanoparticles and CTAB, solution pH, extraction time, and desorption solvent, were optimized. Under optimum conditions, the recoveries of analyses done on samples spiked with the target analytes were between 96.7% and 106.6%; relative standard deviations ranged from 0.4% to 6.6%. The correlation coefficients varied from 0.9993 to 0.9998. The limits of detection ranged from 2.57 to 6.58 ng mL–1 (at a signal-to-noise ratio of 3). The method developed in the present work is feasible for sample pretreatment of herbal medicines.
Keywords: Aloe-emodin, Anthroquinones, Cetyltrimethylammonium bromide (CTAB), Chrysophanol, Emodin, Herbal medicine samples (HMs), Magnetic nanoparticles, Mixed hemimicelles, Physcion, Radix et Rhizoma Rhei, Rhein