Simultaneous determination of flavonoids in Ixeridium gracile by micellar electrokinetic chromatography

A micellar electrokinetic chromatography (MEKC) method has been developed for the quantitative analysis of five flavonoids: luteolin 7-O-glucoside (LG), 2',4'-dihydroxy-dihydrochalcone (DD), 2',4'-dihydroxy-chalcone (DC), 7-hydroxy-flavanone (HF) and quercetin 3-O-galactoside (QG) in Ixeridium gracile with UV detection at 275 nm. The applied voltage was 25 kV and the capillary temperature was kept constant at 25 degrees C. The effects of buffer pH, the concentration of electrolyte and organic modifier on migration behavior were studied. Optimum separation condition was achieved with 15 mM borate, 30 mM sodium dodecyl sulfate (SDS) and 10% (v/v) ethanol at pH 10.5. Regression equations showed good linear relationships (correlation coefficients: 0.9984, 0.9991, 0.9994, 0.9995 and 0.9997) between the peak area of each compound and their concentrations. The relative standard deviations (R.S.D.) of the migration time and peak area were less 1.67 and 3.53% (intra-day), and 1.82 and 3.73% (inter-day), respectively, under the optimum separation conditions. The contents of the five active compounds in I. gracile were determined with satisfactory repeatability and recovery.