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Pressure‐assisted capillary electrophoresis frontal analysis for faster binding constant determination
Author(s) -
Qian Cheng,
Wang Su,
Fu Hengqing,
Turner Robin F. B.,
Li Huihui,
Chen David D. Y.
Publication year - 2018
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.201800049
Subject(s) - capillary electrophoresis , chemistry , binding constant , analytical chemistry (journal) , capillary action , diffusion , electrophoresis , multiphysics , chromatography , materials science , binding site , thermodynamics , finite element method , biochemistry , physics , composite material
Adding external pressure during the process of capillary electrophoresis usually add to the band broadening, especially if the pressure induced flow is significant. The resolution is normally negatively affected in pressure‐assisted capillary electrophoresis (PACE). Frontal analysis (FA), however, can potentially benefit from using an external pressure while avoiding the drawbacks in other modes of CE. In this work, possible impact from the external pressure was simulated by COMSOL Multiphysics®. Under a typical CE‐FA set‐up, it was found that the detected concentrations of analyte will not be significantly affected by an external pressure less than 5 psi. Besides, the measured ligand concentration in PACE‐FA was also not affected by common variables (molecular diffusion coefficient (10 −8 to 10 −11 m 2 /s), capillary length etc ). To provide an experimental proof, PACE‐FA is used to study the binding interactions between hydroxypropyl β‐cyclodextrin (HP‐β‐CD) and small ligand molecules. Taking the HP‐β‐CD /benzoate pair as an example, the binding constants determined by CE‐FA (18.3 ± 0.8 M −1 ) and PACE‐FA (16.5 ± 0.5 M −1 ) are found to be similar. Based on the experimental results, it is concluded that PACE‐FA can reduce the time of binding analysis while maintaining the accuracy of the measurements.