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Applications of on‐line weak affinity interactions in free solution capillary electrophoresis
Author(s) -
Heegaard Niels H. H.,
Nissen Mogens H.,
Chen David D. Y.
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 - 10.1002/1522-2683(200203)23:6<815::aid-elps815>3.0.co;2-v
Subject(s) - capillary electrophoresis , affinity electrophoresis , chemistry , enantiomer , electrophoresis , chromatography , analyte , capillary action , selectivity , molecule , affinity chromatography , biochemistry , materials science , stereochemistry , organic chemistry , enzyme , composite material , catalysis
The impressive selectivity offered by capillary electrophoresis can in some cases be further increased when ligands or additives that engage in weak affinity interactions with one or more of the separated analytes are added to the electrophoresis buffer. This on‐line affinity capillary electrophoresis approach is feasible when the migration of complexed molecules is different from the migration of free molecules and when separation conditions are nondenaturing. In this review, we focus on applying weak interactions as tools to enhance the separation of closely related molecules, e.g. , drug enantiomers and on using capillary electrophoresis to characterize such interactions quantitatively. We describe the equations for binding isotherms, illustrate how selectivity can be manipulated by varying the additive concentrations, and show how the methods may be used to estimate binding constants. On‐line affinity capillary electrophoresis methods are especially valuable for enantiomeric separations and for functional characterization of the contents of biological samples that are only available in minute quantities.