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Chiral capillary electrophoretic separation of amino acids derivatized with 9‐fluorenylmethylchloroformate using mixed chiral selectors of β‐cyclodextrin and sodium taurodeoxycholate
Author(s) -
Chen Fang,
Zhang Shufeng,
Qi Li,
Chen Yi
Publication year - 2006
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.200500855
Subject(s) - enantiomer , chemistry , capillary electrophoresis , resolution (logic) , cyclodextrin , chromatography , electrophoresis , selectivity , amino acid , chiral resolution , sodium , alanine , beta cyclodextrins , analytical chemistry (journal) , stereochemistry , organic chemistry , biochemistry , artificial intelligence , computer science , catalysis
Chiral separation of 19 pairs of amino acid (AA) enantiomers derivatized with 9‐fluorenylmethylchloroformate (FMOC) was successfully conducted by capillary electrophoresis using the mixture of β‐CD and sodium taurodeoxycholate (STDC) as selectors. Resolution was considerably superior to that obtained by using either β‐CD or STDC alone. After a systematic inspection, a buffer composed of 150 mM borate and 18% v/v isopropanol at pH 8.0, dissolved with 30 mM β‐CD and 30 mM STDC, was adopted and able to generate baseline resolution (>1.50) for 17 pairs of FMOC‐AA enantiomers and somewhat lower resolution for arginine (1.36) and alanine (1.18), respectively. Experimental data revealed that the addition of the second selector did not increase the mobility difference between a pair of enantiomers (Δμ = μ D – μ L and the number of theoretical plates ( N ), but decreased the summed apparent mobility of a pair of enantiomers (Σμ = μ D − μ L ), which was mainly due to the decrease of the electroosmotic flow. The variation of Σμ was thus the major reason responsible for the improvement of chiral resolution in this study. The result demonstrated that not only the intrinsic selectivity of the selectors was the basis of the chiral separation, but also the non‐chiral effect of the selectors, the change of the electroosmotic flow, was an important factor in enhancing the enantioseparation resolution. This study could probably help to explain the reasons for resolution improvement in some dual selectors systems, which are not very clear at present.