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Cyclodextrin‐modified monolithic columns for resolving dansyl amino acid enantiomers and positional isomers by capillary electrochromatography
Author(s) -
Chen Zilin,
Ozawa Hiroshi,
Uchiyama Katsumi,
Hobo Toshiyuki
Publication year - 2003
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.200305403
Subject(s) - capillary electrochromatography , chemistry , electrochromatography , monolithic hplc column , chromatography , enantiomer , elution , structural isomer , theoretical plate , cyclodextrin , silica gel , capillary electrophoresis , analytical chemistry (journal) , high performance liquid chromatography , organic chemistry
We describe β‐ and γ‐cyclodextrins (β‐ and γ‐CD)‐modified monolithic columns prepared by sol‐gel process and chemical modifications. The monolithic silica column was fabricated inside a fused‐silica capillary with 100 μm inner diameter by sol‐gel process. The monolithic silica matrix was chemically modified chiral selectors of β‐ or γ‐CDs with a spacer of 3‐glycidoxypropyltrimethoxysilane by on‐column reactions. γ‐CD‐modified monolithic column has successfully been applied for the separation of dansyl amino acid enantiomers. β‐CD‐modified monolithic column has been used for the separation of the positional isomers of o‐, m‐ , and p‐ cresols and the enantioseparation of racemates of benzoin and several dansyl amino acids by capillary electrochromatography, respectively. For the separation of neutral positional isomers, a positive electric field was applied. However, for the separation of negatively charged analytes, a negative electric field was applied at the inlet of column. The separation efficiency of 5.0×10 4 theoretical plates/m for dansyl‐ L ‐threonine was obtained at electric field strength of −300 V/cm in the mobile phase of 50 m M 2‐( N ‐morpholino)ethanesulfonic acid (MES)‐Tris/methanol (70/30) buffer at pH 7.0. L ‐Enantiomers were eluted as the first peak. Scanning electron micrograph showed that monolithic columns have the morphology of continuous skeleton and large through‐pores.