Enantioseparation of N-derivatized amino acids by micro-liquid chromatography using carbamoylated quinidine...

In order to obtain satisfactory column permeability, efficiency and selectivity for micro-HPLC, a capillary monolithic column containing O-9-[2-(methacryloyloxy)-ethylcarbamoyl]-10,11-dihydroquinidine (MQD) as chiral selector was re-optimized. The monolithic column was used to successfully enantioresolve a wide range of N-derivatized amino acids including alanine, leucine, methionine, threonine, phenylalanine, valine, serine, isoleucine, tryptophan, and cysteine. The influence of mobile phase parameters, such as the organic solvent type and concentration, the apparent pH, and buffer concentration, on retention and enantioseparation of N-derivatized amino acids has been investigated. 3,5-dinitrobenzoyl-amino acids and 3,5-dichlorobenzoyl-amino acids were resolved into enantiomers with exceptionally high selectivity and resolution. The chemoselectivity of the monolithic column for a multicomponent mixture of N-derivatized amino acids was also investigated. A mixture of three pairs of 3,5-dichlorobenzoyl-amino acids could be fully resolved in 22.5 min.