Enantioseparation of aromatic amino acids and amino acid esters by capillary electrophoresis with crown ether and prediction of enantiomer migration orders by a three-dimensional quantitative structure-property relationship/comparative field analysis model.
The complete enantioseparations of eight aromatic amino acids and four alkyl esters of 2-phenylglycine were achieved by chiral capillary electrophoresis employing 20 mM Tris-citric acid background electrolyte (pH 2.50) containing 5.0 mM of (+)-18-crown-6-tetracarboxylic acid. The relative migration times (RMTs) to that of 6-aminonicotinic acid were characteristic of each enantiomer with good within-day precisions (% relative standard deviation (RSD) < or = 2.0). Quantitative structure-property relationship (QSPR) modeling based on comparative molecular field analysis (CoMFA) was performed to investigate the correlation between the molecular field descriptor values of each enantiomer studied as analyte and its RMT. The resulting CoMFA model allowed reliable prediction for the RMT values (q2= 0.406, r2 = 0.996), thus being expected to become a valuable tool to predict enantiomer migration orders (EMOs) of amino acids and amines whose pure enantiomers are unavailable. The CoMFA steric fields supported the well-established chiral recognition mechanism based on molecular interaction between chiral selector (+)-18-crown-6-tetracarboxylic acid and amino acid enantiomers.
Park
Hyun-Ju
HJ
College of Pharmacy, Sungkyunkwan University, Suwon, South Korea.
Choi
Youngmie
Y
Lee
Wonjae
W
Kim
Kyoung-Rae
KR
D024322:Amino Acids, Aromatic / Q000737:chemistry* / Q000302:isolation & purification*; D043844:Crown Ethers; D019075:Electrophoresis, Capillary / Q000379:methods*; D004951:Esterification; D005998:Glycine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000302:isolation & purification; D008958:Models, Molecular; D021281:Quantitative Structure-Activity Relationship; D013237:Stereoisomerism
D024322:Amino Acids, Aromatic; D043844:Crown Ethers; C090732:18-crown-6 2,3,11,12-tetracarboxylic acid; D005998:Glycine