Capillary electrophoretic separation of estrogens using anionic sulfobutyl ether beta-cyclodextrin

The determination of estrogens is important for the diagnosis of reproductive diseases and for monitoring the normal process of pregnancy. Previous separations of estrogens by capillary electrophoresis have employed a combination of cyclodextrins and surfactants. This paper describes the complete separation of five estrogens, 2-hydroxyestrone, 2-methoxyestradiol, estrone, estriol, and 17 alpha-estradiol, using sulfobutyl ether beta-cyclodextrin as the buffer additive. In this case, the separation can be accomplished with good efficiency without the addition of a surfactant or organic modifier to the run buffer.