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Enantioseparation of chiral aromatic amino acids by capillary electrophoresis in neutral and charged cyclodextrin selector modes
Author(s) -
La Sookie,
Ahn Sungyeon,
Kim JungHan,
Goto Junichi,
Choi OneKyun,
Kim KyoungRae
Publication year - 2002
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200290030
Subject(s) - enantiomer , chemistry , capillary electrophoresis , amino acid , aromatic amino acids , cyclodextrin , phenylalanine , tryptophan , chromatography , resolution (logic) , mimosine , stereochemistry , biochemistry , botany , artificial intelligence , computer science , leucaena leucocephala , biology
Simultaneous enantioseparations of 15 racemic aromatic amino acids and L ‐mimosine for their chiral discrimination were achieved by neutral selector‐modified capillary electrophoresis (CE) and by charged selector‐modified CE. Among the diverse cyclodextrins (CDs) examined, hydroxypropyl (HP)‐α‐CD as the neutral selector and highly sulfated (HS)‐γ‐CD as the charged selector provided best chiral environments of different enantioselectivities. Fairly good enantiomeric resolutions were achieved with the HP‐α‐CD mode except for racemic 6‐hydroxy‐3,4‐dihydroxyphenylalanine, threo‐ 3,4‐dihydroxyphenylserine and homophenylalanine while high‐resolution separations of all the enantiomeric pairs were achieved in the HS‐γ‐CD mode except that L ‐mimosine was not detected and a partial resolution (0.6) for threo ‐3,4‐dihydroxyphenylserine enantiomers. Relative migration times to that of internal standard under the respective optimum conditions were characteristic of each enantiomer with good precision (% RSD: 0.7–3.8), thereby enabling to cross‐check the chemical identification of aromatic amino acids and also their chiralities. The method linearity was found to be adequate ( r > 0.99) for the chiral assay of the aromatic amino acids investigated. When applied to extracts of three plant seeds, nonprotein amino acids such as L ‐mimosine (42 νg/g) from Mimosa pudica Linné, and L ‐3,4‐dihydroxyphenylalanine (268 νg/g) from Vicia faba were positively detected along with L ‐tryptophan, L ‐phenylalanine and L ‐tyrosine.