Evaluation of the liquid-chromatographic resolution of indenoindolic racemic compounds on three protein-based chiral stationary phases.
ABSTRACT Three liquid-chromatography columns, containing immobilized proteins as chiral stationary phases (CSPs) were investigated for the direct separation of enantiomers of racemic indenoindolic compounds. By using an experimental design the effects of column temperature, pH, ionic strength, and type and concentration of organic solvent in the mobile phase on retention and resolution of racemic substances were systematically studied. The three CSPs investigated consisted of alpha(1)-acid glycoprotein (Chiral-AGP), bovine serum albumin (BSA-DSC) and ovomucoid (Ultron ES-OVM). The two enantiomers of all studied compounds could be separated on at least one of the three CSPs, which have different enantioselective properties.
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ABSTRACT: The chiral‐AGP column is a protein based HPLC column widely used for analysis of chiral compounds in pharmaceutical and pharmacological applications. Organic solvents are frequently used as mobile phase additives to control analyte retention. In many cases, switching from one solvent additive to another can influence the enantioselectivity as well as retention. The group of solvents typically used as mobile phase additives includes methanol, ethanol, 1‐propanol, 2‐propanol, and acetonitrile. In this study, the column was used to resolve four different N‐substituted amino acid derivatives. The mobile phase consisted of a pH 7 phosphate buffer with the addition of organic solvent to control retention. During method optimization, nine different organic solvent additives were compared, including two tertiary alcohols. For three of the four analytes, the tertiary alcohol additives provided significantly higher enantioselectivity than any of the commonly recommended solvent additives, affording enantioselectivities in the range of 1.4 to 3.8.Journal of Liquid Chromatography & Related Technologies - J LIQ CHROMATOGR RELAT TECHNO. 01/2006; 29(18):2625-2640.