title: Separation and determination of isoflavones in red clover by micellar electrokinetic capillary chromatography.
abstract: A micellar electrokinetic capillary chromatography (MECC) method has been developed for the determination of the four isoflavones, i.e. biochanin A, formononetin, genstein and daidzein in red clover (Trifolium Pratense L.). The effect of running buffer pH and concentration were investigated. An electrolyte composed of 30 mm borate, 20 mm sodium dodecyl sulfate (SDS) and 4 mg/mL HP-beta-CD containing 5% (v/v) ethanol at pH 10.1 provides a satisfactory separation for all the analytes. The applied voltage was 25 kV, and the capillary temperature was kept constant at 25 degrees C with a UV detection at 254 nm. The relative standard deviations (RSD) of the migration time and peak area were less than 1.73 and 3.94% (intra-day), and 2.29 and 4.38% (inter-day), respectively, under the optimized separation conditions. Regression equations revealed a good linear relationship between the peak area of each compound and its concentration. The contents of the four compounds in red clover were successfully determined with satisfactory repeatability and recovery.
authors.affiliation: Key Laboratory for Natural Medicine of Gansu Province, Lanzhou Institute of Chemical Physics, Chinese Academy of Sciences, Lanzhou 730000, People's Republic of China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhang
authors.forename: Juan
authors.initials: J
authors.lastname: Chen
authors.forename: Liang
authors.initials: L
authors.lastname: Zhao
authors.forename: Yan-Ping
authors.initials: YP
authors.lastname: Shi
mesh_terms: D001888:Boric Acids / Q000737:chemistry; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D007529:Isoflavones / Q000032:analysis* / Q000302:isolation & purification; D029902:Medicago / Q000737:chemistry*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D047392:beta-Cyclodextrins / Q000737:chemistry
chemical_list: D001888:Boric Acids; D007529:Isoflavones; D047392:beta-Cyclodextrins; D012967:Sodium Dodecyl Sulfate; C031215:betadex; C032688:boric acid