Study on the Enantiomeric Separation of Adrenalines by Capillary Zone Electrophoresis
毛细管区带电泳法研究肾上腺素类药物的手性分离

Capillary zone electrophoresis (CZE) has been used for the enantiomeric separation of the racemic isoprenaline, noradrenaline and adrenaline with bare fused silica capillary and employing beta-cyclodextrin(beta-CD) and beta-cyclodextrin derivatives as the chiral selectors. Both the complexion and enantiomeric resolution were influenced by the temperature, beta-CD type, CD concentration and pH of background electrolyte (BGE). The effects of the BGE types and concentrations on the enantiomeric separation were also investigated. The results showed that 2,6-di-O-carboxymethyl-beta-cyclodextrin (CM-beta-CD) has stronger recognition than that of beta-CD for the chiral separation of the basic drugs under study. The CD concentrations and pH of BGE have strong influence on the efficiency of chiral separation. The adsorption of the basic compound on the surface of bare fused silica capillary is a disadvantage to the chiral separation while the use of beta-CD as the chiral selector and the addition of an amphiphile, such as tetraethylammonium bromide (TEA+) or tetrabutylammonium bromide (TBA+) to the BGE could improve the resolution of the enantiomers due to the reduction of the adsorption of the basic compound on the silica surface by the strong electrostatic force between the positively charged amphiphile and the silica surface. It was also found that as CM-beta-CD was used as the chiral selector there was no influence on the chiral separation of the basic compound whether the amphiphile was added to BGE or not. Lower temperature was favorable to improve the efficiency of the chiral separation. CM-beta-CD gave a baseline enantiomeric separation for isoprenaline, while beta-CD, under the same experimental conditions, gave an incomplete chiral separation. Both CM-beta-CD and beta-CD could not give enantiomeric resolution for noradrenaline and adrenaline.