Analysis of Flavonoids in Flos Genkwa by β-cyclodextrin and Ionic Liquid Modified Capillary Zone Electrophoresis

A β-cyclodextrin (β-cd) and ionic liquid (1-ethyl-3-methylimidazolium tetrafluroborate, 1e-3mi-tfb) modified capillary zone electrophoretic (cze) method has been developed to determine three flavonoids (genkwanin, apigenin and luteolin) in flos genkwa with 4-methylumbelliferone as internal standard. the effects of buffer ph and concentration, β-cd concentration and ionic liquid on separation were investigated. the optimum electrophoretic conditions are as follows: 20 mmol·l-1 tetraborate (ph 9.0)- 6 mmol·l-1 β-cyclodextrin-0.04 % 1e-3mi-tfb (v/v) as the running buffer, applied voltage of 25 kv. under the optimized conditions, the calibration curves of the three flavonoids all showed excellent linearity in the 1~100 µg· ml-1 range. the relative standard deviation in migration time and peak area was 0.21 % and 2.92 % for genkwanin, 0.15 % and 2.33 % for apigenin, 0.28 % and 3.35 % for luteolin. the detection limits of the three flavonoids ranged from 0.26 to 0.32 µgּml-1. the recoveries of the three flavonoids ranged between 94.3 % and 103.5 %