The separation of green tea catechins by micellar electrokinetic chromatography

✍ Scribed by Bryant C. Nelson; Jeanice Brown Thomas; Stephen A. Wise; Joseph J. Dalluge

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 188 KB
• Volume: 10
• Category: Article
• ISSN: 1040-7685
• DOI: 10.1002/(sici)1520-667x(1998)10:8<671::aid-mcs6>3.0.co;2-a

✦ Synopsis

A micellar electrokinetic chromatographic MEKC separation system was developed for the efficient separation of biologically and clinically important Ž . green tea catechins. Six structurally isomeric tea catechins, e.g., y epigallo-Ž . Ž . Ž . Ž . catechin-3-gallate EGCG , y epicatechin gallate ECG , y gallocatechin gal-Ž . Ž . Ž . Ž . Ž .

Ž . late GCG , y epigallocatechin EGC , y epicatechin EC , and q catechin Ž . C , were effectively separated using a tetraboratersodium dodecyl sulfate Ž . SDS r␤-cyclodextrin micellar buffer system. The effects of several critical separa-Ž tion parameters micelle charge type, surfactant type, organic solvent buffer . modifier, micelle concentration, buffer pH, and cyclodextrin buffer modifier were evaluated for enhanced isomer separation and resolution. The pH was shown to be a strong factor influencing the separation of the isomers, but baseline resolution of all six structural isomers was only effected when a micellar buffer system contained ␤-cyclodextrin buffer modifier. The proficiency of the developed method was tested Ž . by determining the analytical levels mgrg of crude catechins in aqueous extrac-Ž . tions of three varieties of green tea Camellia sinesis .