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A dynamic molecular probe to investigate catalytic effects and Joule heating in enantioselective MEKC
Author(s) -
Trapp Oliver
Publication year - 2007
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.200600596
Subject(s) - chemistry , micelle , enantiomer , enantioselective synthesis , sodium , analytical chemistry (journal) , sodium methoxide , sodium cholate , chromatography , aqueous solution , catalysis , stereochemistry , organic chemistry
Enantiomerization of ferroin [tris(1,10‐phenanthroline)‐iron(II)‐complex] was investigated by enantioselective dynamic micellar EKC. The enantiomer separation was performed in an aqueous 50 mM sodium borate/sodium dihydrogenphosphate buffer at pH 8.0 in the presence of the chiral surfactant sodium cholate. The unified equation of dynamic chromatography was employed to determine reaction rate constants from the electropherograms featured with distinct plateau formation. Activation parameters Δ H ≠ = 124.0 ± 0.5 kJ/mol and Δ S ≠ = 121 ± 1 J·K −1 mol −1 were calculated from temperature‐dependent measurements between 10.0 and 27.5°C in 2.5 K steps. Considering the data obtained by polarimetry of enantiomeric pure ferroin in water, it was found that enantiomerization rate in the micelle is accelerated by a factor of 12. Because of the highly positive activation entropy Δ S ≠ , ferroin was used as a temperature‐sensitive dynamic molecular probe to determine temperature deviations caused by Joule heating.