A Novel Selective Accelerated Solvent Extraction for Effective Separation and Rapid Simultaneous Determination of Six Anthraquinones in Tartary Buckwheat and Its Products by UPLC–DAD

A novel analytical method is developed for effective separation and rapid simultaneous determination of anthraquinones in Tartary buckwheat by ultra-performance liquid chromatography coupled to a diode array detector (UPLC−DAD). A selective accelerated solvent extraction (SASE) procedure combines an accelerated solvent extraction (ASE) and cleanup in situ. SASE conditions were investigated and optimized in the details. Methanol/acetone (50:50, v / v ) was selected as solvent for the extraction, and silica gel was selected as sorbents for clean-up. The SASE procedure simplified further the entire sample preparation chain and achieved satisfactory results in the analyses of anthraquinones compared with traditional extraction methods. The effective separation of six anthraquinones from an extract of Tartary buckwheat on an Acquity BEH C 18 (2.1 mm × 50 mm, 1.7 μm) column using gradient elution was achieved within 7 min. Good linearity was achieved, with a correlation coefficient ( r 2 ) of ≥0.9998. The limit of detection (LOD) and the limit of quantification (LOQ) were in the range of 0.033–0.067 μg/mL and 0.1–0.2 μg/mL, respectively. Under the optimized conditions, good recovery (98.3–109 %) of the anthraquinones was achieved. The validated method is successfully applied to the quality assurance of the anthraquinones in Tartary buckwheat and its products.