Page 66 - Chiral Separation Techniques

42 2 Method Development and Optimization of Enantiomeric Separations Using …

A B C

D E F

Fig. 2-8. Chromatograms of ketoprofen in reversed phase on: vancomycin (A), teicoplanin (B), risto-
cetin A (C), vancomycin + teicoplanin (D), ristocetin A + teicoplanin (E), and ristocetin A + vancomycin
+ teicoplanin (F). All columns were 100 × 4.6 mm. The numbers by the peaks refer to the retention time
in minutes. The mobile phase was methanol: 0.1 % triethylammonium acetate (25/75 v/v) pH 6.0. The
–1
flow rate was 1.0 mL min at ambient temperature (23 °C).

the selectivity could be lost on the coupled R+T or R+V columns. Therefore, it is the
preferred tactic to couple only vancomycin and teicoplanin in normal phase.
Column coupling proves to be a rapid screening approach in identifying chiral
selectivity in the most efficient and economical way. In addition to the potential for
the simultaneous analysis of a mixture, the coupling practice offers the advantages