Simultaneous determination of myricetrin, quercitrin and afzelin in leaves of Cercis chinensis by a fast and effective method of ionic liquid microextraction coupled with HPLC.

In this study, the contents of myricetrin, quercitrin and afzelin in Cercis chinensis leaves were determined simultaneously by 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM] BF₄/70% ethanol microextraction combined with High Performance Liquid Chromatograph (HPLC) analysis. The mobile phase was eluted with an Agilent ZORBAX SB-C18 column (4.6 mm×5 mm, 5 μm), B was methanol and C was 0.1% glacial acetic acid-water as the mobile phase. The flow rate was 0.8 mL min^-1, eluents was detected at 245 nm at column temperature of 30 °C. The orthogonal experiment and variance analysis were used to determine the optimum process of C. chinensis leaves by the comprehensive evaluation of the contents of myricetrin, quercitrin and afzelin. The results showed that the injection rates of myricetrin, quercitrin and afzelin were in the range of 0.4997-18.73 μg (r = 0.9997), 0.1392-5.218 μg (r = 0.9998) and 0.04582-1.718 μg (r = 0.9998), respectively. The optimum conditions were determined as follows: the concentration of extraction, 0.9 mol/L; the ultrasonic time, 50 min; the solid-liquid ratio, 1:30; the centrifugal speed, 5000 r/min, and the crushing ratio, 90 mesh. Under these optimal conditions, the average levels of myricetrin, quercitrin and afzelin were 8.6915, 1.5865 and 1.0920 (mg/g), respectively.