High-performance liquid chromatographic separation of peptide and amino acid stereoisomers

Several high-performance liquid chromatographic (HPLC) methods are described for separation of peptide stereoisomers which are not well resolved by traditional reversed-phase chromatography. These chiral HPLC methods include investigations with a beta-cyclodextrin column, a Pirkle D-Phenyl Glycine column and a Chiral-Pak WH column. A method based on derivatization of dipeptides with a chiral reagent, N-acetyl-L-cysteine and o-phthalaldehyde, is also discussed. A series of linear and cyclic dipeptides and modified amino acids were chromatographed on the four systems. Resolution varied for the four different systems depending on the types of compounds that were chromatographed.