New ligand exchange chiral stationary phase for the liquid chromatographic resolution of α- and β-amino acids

Abstract

A new ligand exchange chiral stationary phase (CSP) has been developed by covalently bonding ( R)- N, N-carboxymethyl undecyl phenylglycinol mono-sodium salt onto silica gel and applied in the resolution of α- and β-amino acids. In the resolution of α-amino acids, the new CSP was better in some cases than the old one, which was previously developed by covalently bonding ( S)- N, N-carboxymethyl undecyl leucinol mono-sodium salt onto silica gel, but worse in some other cases than the old one in terms of the separation factors ( α). However, the new CSP was always much better than the old one in terms of the resolution factors ( R s ). In the resolution of β-amino acids, the new CSP was always much better than the old one in terms of both the separation and resolution factors. In an effort to characterize the new CSP, the chromatographic behaviors for the resolution of selected α- and β-amino acids were investigated with the variation of the content of organic modifier and Cu(II) concentration in aqueous mobile phase and the column temperature.