LC Enantioseparation of β-Amino Acids on a Crown Ether-Based Stationary Phase
ABSTRACT Reversed-phase high-performance liquid chromatographic methods were developed for the enantioseparation of ten unusual β-3-homo-amino
acids. The underivatized analytes were separated on a chiral stationary phase containing (+)-(18-crown-6)-2,3,11,12-tetracarboxylic
acid as chiral selector. The effects of organic and acidic modifiers and the mobile phase composition on the separation were
investigated. The structures of the substituents in the β position substantially influenced the retention and resolution.
The elution sequence was determined in some cases: the S enantiomers eluted before the R enantiomers.
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ABSTRACT: In this study we describe the enantioseparation of aromatic β3-amino acids by precolumn derivatization with o-phthaldialdehyde and N-isobutyryl-l-cysteine. Derivatization conditions were studied in detail for (R,S)-β-phenylalanine and (R,S)-β-tyrosine revealing a reaction time of 1 min and a molar ratio of the reagents β³-amino acid to o-phthaldialdehyde to N-isobutyryl-l-cysteine of 1:25:25 as optimal. The method was validated for (R,S)-β-phenylalanine in a bacterial cell extract. The analysis provided excellent specificity and reproducibility. The limit of quantification was 25 pmol per 0.5 μL injection. The method could be successfully transferred to the enantioseparation of other β³-amino acids. Enantioseparation of all studied compounds could be achieved in 4–11 min.Chromatographia 01/2010; 71(11):1063-1067. · 1.44 Impact Factor