Determination of curcumins in turmeric by micellar electrokinetic capillary chromatography

A rapid method for the determination of curcumins in Chinese herbal medicine turmeric by micellar electrokinetic capillary chromatography ( MEKC) has been developed. Curcumin, dimethoxy curcumin and bis-dimethoxy curcumin were separated in less than 10 minutes using a 60 cm x 50 mu m I.D uncoated fused-silica capillary column with a buffer consisting of 25 mM hydroxypropyl-beta-CD ( HP-beta-CD), 10% methanol, 40 mM sodium borate and 40 mM SDS ( pH 9.50). The recovery efficiencies were 95.7-106.3%. The calibration curves exhibited good linearity in the range of 90-1220 mu g/mL ( R = 0.9996) for curcumin, 80-1120 mu g/mL ( R = 0.9998) for dimethoxy curcumin and 80-1200 mu g/mL ( R = 0.9998) for bis-dimethoxy curcumin. Contents of curcumins in a methanol extract of turmeric sample could easily be determined by this method. The effect of pH, buffer, surfactant and organic modifier concentration on the migration behavior of the solutes were discussed.