Modelling of the competitive isotherms and the chromatographic separation of two enantiomers

✍ Scribed by Andreas Seidel-Morgenstern; Georges Guiochon

• Publisher: Elsevier Science
• Year: 1993
• Tongue: English
• Weight: 999 KB
• Volume: 48
• Category: Article
• ISSN: 0009-2509
• DOI: 10.1016/0009-2509(93)80189-w

✦ Synopsis

AbstrPti-Using

Frontal analysis, we measured the adsorption isotherms of-h T~figer's baseenantiomers on microcrystalline cellulose triacetab, with bthtiol iis tilvent. The &therm of the first &ted (-k emnti~mer EUII be desLribed satisfactorily by the Langmuir Bquation. The isotherm of rhe (+)-enantiomer hw an inflection point and can be modelled by a quadratic isotherm equation. As a conseequen~., Beth the retention time of the (fkenantiomer and the resolution of a racemi c mixture increase with inrreasing concentration in a certain range. Using the pure enantiomer isotherms and the equilibrium-di~persive model, we wuJd calculate the elution profiles of racemic mih;turs of the IWO enantiomsrs. At low sample sizes, the bands a~ well re~lved the competition between the two enantiomers can be negEemad in rhe calculations, and satiskwmry band profiles are obtained for the racers 'c mixture. At high conmntrakmq the ideal adsorbed solution (IAS) theory was applied to predict the competitive isotherms. Experimsnral data on the separation OF racemic mixtures at high concentmtions, including the individual band profiles, are well represented by the results of calculations mzrde with these isotherms.