Rapid Separation and Determination of 5 Kinds Flavonoids in Astragali Radix Based on Ultra-performance Convergence Chromatography

Abstract

A method was developed for the rapid separation and determination of 5 kinds flavonoids (calycosin, calycosin-7-O-beta-D-glucoside, ononin, medicarpin and formononetin) in Astragali Radix based on ultra. performance convergence chromatography. After extracting by 80% ethanol, the flavonoids were separated on a Waters Acquity UPC2 CSH (100 mm x 3.0 mm i. d., 1.8 mu m) column at 40 degrees C by using supercritical CO2-methanol (contain 0.2% H3PO4) acetonitrile as the mobile phase at a flow rate of 0.4 mL/min, and then analyzed by a UV detector at wavelength of 280 nm, the whole analysis progress was only 15 min. The results showed that the limits of detection (LOD) and the limits of quantitation (LOQ) of five flavonoids were between 0.3 and 0.5 mg/kg, and 1.0 and 2.0 mg/kg, respectively. The spiked recoveries were more than 99.7%, and the relative standard deviations (RSD) were less than 2.2% (n = 6). Under the optimal conditions, 13 groups of Astragali Radix from different producing areas were detected. The contents of calycosin, calycosin-7-O-beta-D-glucoside, medicarpin, ononin and formononetin were 4.8-102 mg/kg, 14-277 mg/kg, 0-135 mg/kg, and 5.3-119 mg/kg, 2.8-41 mg/kg, respectively. This method is simple, fast, accurate and reproducible, and the result is reliable. The method is applicable for the determination of 5 flavonoids in Astragali Radix.