New chiral crown ether stationary phase for the liquid chromatographic resolution of α-amino acid enantiomers

A new chiral stationary phase (CSP) for the liquid chromatographic separation of enantiomers was prepared by bonding a novel enantiopure (diphenyl-substituted 1,1′-binaphthyl) crown ether to 5 μm silica gel. The resulting CSP was applied to the separation of the enantiomers of various natural and unnatural α-amino acids. All α-amino acids tested were resolved very well on the new CSP, with the exception of proline, which does not contain a primary amino group. The resolution of α-amino acid enantiomers on this new CSP was found to be dependent on the type and amounts of organic and acidic modifiers, and on column temperature.