HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC ENANTIOSEPARATION OF N-PROTECTED ALPHA-AMINO-ACIDS USING NONPOROUS SILICA MODIFIED BY A QUININE CARBAMATE AS CHIRAL STATIONARY-PHASE

In this study, tert-butyl carbamoylated quinine as chiral selector was immobilized on nonporous silica (NPS) 1.5 mu m particles developed by MICRA, and this new chiral stationary phase (CSP) was packed into a 3 .3 cm column (4.6 mm ID). A series of various N-protected alpha-amino acids was chosen as chiral selectands, including 3,5-dinitrobenzyloxyc arbonyl amino acids(DNZ-AAs). In order to optimize the chromatographic conditions with this novel CSP and to apply it to the resolution of a cidic analytes, the following parameters have been varied and studied: pH of the mobile phase, buffer concentration, and percentage of metha nol or acetonitrile in the mobile phase. DryLab(R) software was applie d to optimize enantioseparation by simulating chromatographic function s of experimental conditions for isocratic and/or gradient runs. Thus, we were able to resolve a set of test compounds within several minute s, whereby our attention was particularly drawn to the resolution of D NZ-AA derivatives. (C) 1997 Wiley-Liss, Inc.