HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHIC SEPARATION OF CIS-TRANS-ISOMERS OF PROLINE-CONTAINING PEPTIDES .1. SEPARATION ON CYCLODEXTRIN-BONDED SILICA

Beta-Cyclodextrin-bonded silica is shown to be a suitable stationary phase for high-performance liquid chromatography of conformational isomers of proline-containing peptides. A variety of selective interactions may be used to separate cis-trans conformers by steric discrimination. The formation of an inclusion complex seems to be particularly effective if an aromatic amino acid N-terminal-bonded to proline is enclosed in the analyte. Unusually high resolution values for such separations under low-temperature conditions suggest a steric hindrance of isomer conversion owing to the formation of inclusion complexes.