Determination of Flavonoids from Paulownia tomentosa (Thunb) Steud by Micellar Electrokinetic Capillary Electrophoresis

A micellar electrokinetic capillary electrophoresis (MEKC) method was developed for the determination of three flavonoids: diplacone (DI), mimulone (MI) and apigenin (AP) in the flowers of Paulownia tomentosa (Thunb) Steud. A buffer solution (pH 10.00) of 20 mM sodium borate, 10 mM sodium dodecyl sulfate (SDS) and 5% methanol was found to be the most suitable electrolyte for this separation. Regression equations revealed linear relationships (correlation coefficients: 0.9997 and 0.9998) between the peak area of each compound (DI, MI and AP) and its concentration. The relative standard deviations of migration times and peak areas were < 1.93 and 6.84%, respectively. The effects of pH, surfactant (SDS) concentration and organic modifier (methanol) on migration were also studied. The contents of three flavonoids in the extracts from the flowers of P. tomentosa applying different solvents were successfully determined within 12 min.