Complementary enantioselectivity profiles of chiral cinchonan carbamate selectors with distinct carbamate residues and their implementation in enantioselective two-dimensional high-performance liquid chromatography of amino acids

摘要: Abstract A cardinal requirement for effective 2D-HPLC separations is sufficient complementarity in the retention profiles of first and second dimension separations. It shown that enantioselectivity chiral selectors derived from cinchona alkaloids can be conveniently modulated by structural variation carbamate residue quinine/quinidine ligand such stationary phases (CSP). variety aliphatic aromatic residues have been tested comparison to non-carbamoylated quinine CSP. Various measures orthogonality utilized derive CSP most complementary tert-butylcarbamoylated (tBuCQN CSP), which commercially available as Chiralpak QN-AX column. turned out O-9-(2,6-diisopropylphenylcarbamoyl)-modified promising this respect. Its implementation a separation amino acids derivatized with Sanger’s reagent (2,4-dinitrophenylated acids) combined tBuCQN revealed successful enantiomer comprehensive chiral×chiral setup. However, degree could greatly enhanced when simultaneously absolute configurations were exchanged quinidine selector resulting opposite elution orders enantiomers two dimensions. The advantage over achiral×chiral setup, amongst others, perfect compatibility mobile phase because both dimensions identical eluent used.