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Separation of Tryptophan Enantiomers by Ligand‐Exchange Chromatography With Novel Chiral Ionic Liquids Ligand
Author(s) -
Qing Haiqun,
Jiang Xinyu,
Yu Jingang
Publication year - 2014
Publication title -
chirality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.43
H-Index - 77
eISSN - 1520-636X
pISSN - 0899-0042
DOI - 10.1002/chir.22286
Subject(s) - chemistry , enantiomer , ligand (biochemistry) , tryptophan , methanol , chirality (physics) , chiral ligand , ionic liquid , amino acid , chromatography , medicinal chemistry , inorganic chemistry , stereochemistry , organic chemistry , enantioselective synthesis , catalysis , biochemistry , nambu–jona lasinio model , receptor , chiral symmetry breaking , physics , quantum mechanics , quark
Chiral ionic liquids (CILs) with amino acids as cations have been applied as novel chiral ligands coordinated with Cu 2+ to separate tryptophan enantiomers in ligand exchange chromatography. Four kinds of amino acid ionic liquids, including [L‐Pro][CF 3 COO], [L‐Pro][NO 3 ], [L‐Pro] 2 [SO 4 ], and [L‐Phe][CF 3 COO] were successfully synthesized and used for separation of tryptophan enantiomers. To optimize the separation conditions, [L‐Pro][CF 3 COO] was selected as the model ligand. Some factors influencing the efficiency of chiral separation, such as copper ion concentration, CILs concentration, methanol ratio (methanol/H 2 O, v/v), and pH, were investigated. The obtained optimal separation conditions were as follows: 8.0 mmol/L Cu(OAc) 2 , 4.0 mmol/L [L‐Pro][CF 3 COO] ,and 20% (v/v) methanol at pH 3.6. Under the optimum conditions, acceptable enantioseparation of tryptophan enantiomers could be observed with a resolution of 1.89. The results demonstrate the good applicability of CILs with amino acids as cations for chiral separation. Furthermore, a comparative study was also conducted for exploring the mechanism of the CILs as new ligands in ligand exchange chromatography. Chirality 26:160–165, 2014 . © 2014 Wiley Periodicals, Inc.