Analysis of sesquiterpene lactones in Magnolia grandiflora L. by micellar electrokinetic capillary chromatography

Five sequiterpene lactones found in Magnolia grandiflora were successfully separated by micellar electrokinetic capillary chromatography (MECC). Separ ation parameters were studied systematically, and the best results were obt ained with a phosphate-bo rate buffer at pH 7.25, containing the bile salt sodium cholate as surfactant and isopropanol as organic modifier, Optimum t emperature, voltage and detection wavelength were 30 degreesC, 20 kV and 21 0 nm, respectively. This setup allowed a baseline separation of the standar d compounds within 12 min, with a detection limit of 4.7 mug . mL(-1) or le ss. A quantitative analysis of different M. grandiflora samples showed part henolide as the most dominant sesquiterpene lactone in all specimens, with concentrations ranging from 0.019% in fruits to 0.335% in leaves (w/w).