Impact of amines as co-modifiers on the enantioseparation of various amino acid derivatives on a tert-butyl carbamoylated quinine-based chiral stationary phase

A tert-butyl carbamoylated quinine-based chiral stationary phase (CSP) for direct enantiomer separation of various natural and unnatural amino acid derivatives was studied. The influence of functional groups in the amino acid side chains upon the enantioseparation is discussed with the aim of realizing contributions to their overall chiral recognition. The effects of various amines as co-modifiers upon retention and overall enantioselectivity of amino acid derivatives in polar organic solvents was systematically investigated. In general, retention times decreased with increasing amine concentrations without a distinct alteration of enantioselectivity. All analytes were rapidly resolved on the CSP with the methanol-based mobile phase containing 87 mM acetic acid and 7 mM triethylamine.