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The separation of the enantiomers of several a-amino acids was studied on a new chiral stationary phase (CSP) which is based on the macrocyclic glycopeptide antibiotic eremomycin attached to silica particles. Retention and separation factors were determined under analytical conditions at ambient temperature for different mobile phase compositions. In order to evaluate the potential with respect to preparative separations the adsorption isotherms of D- and L-methionine were determined for one mobile phase composition applying the elution by characteristic point method. The isotherms were validated by comparing experimentally determined elution profiles with predictions based on the equilibrium dispersive model. Finally, the performance of the eremomycin CSP was compared with a commercially available CSP based on the macrocyclic antibiotic teicoplanin. After determining the isotherms of D- and L-methionine also for the teicoplanin phase, the equilibrium dispersive model was used for both CSP to identify optimal operating conditions. For the separation and conditions considered the new eremomycin CSP revealed a better performance compared to the teicoplanin CSP.

Within the pharmaceutical industry and in biotechnology there is an increasing need for selective and efficient separation technologies to isolate and purify value-added products. A hybrid process approach combining chromatography and fractional crystallization is studied below. The work presented is concerned with the application and evaluation of this concept in order to isolate a certain pharmaceutical intermediate from a binary mixture. A comparison with performing the same separation exclusively in a single chromatographic process is given also.

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