Тип публикации: статья из журнала
Год издания: 2016
Идентификатор DOI: 10.1093/chromsci/bmw057
Аннотация: The influence of analyte concentration when compared with the concentration of a charged ligand in background electrolyte (BGE) on the measured values of electrophoretic mobilities and stability constants (association, binding or formation constants) is studied using capillary electrophoresis (CE) and a dynamic mathematical simulatПоказать полностьюor of CE. The study is performed using labile complexes (with fast kinetics) of iron (III) and 5-sulfosalicylate ions (ISC) as an example. It is shown that because the ligand concentration in the analyte zone is not equal to that in BGE, considerable changes in the migration times and electrophoretic mobilities are observed, resulting in systematic errors in the stability constant values. Of crucial significance is the slope of the dependence of the electrophoretic mobility decrease on the ligand equilibrium concentration. Without prior information on this dependence to accurately evaluate the stability constants for similar systems, the total ligand concentration must be at least >50-100 times higher than the total concentration of analyte. Experimental ISC peak fronting and the difference between the direction of the experimental pH dependence of the electrophoretic mobility decrease and the mathematical simulation allow assuming the presence of capillary wall interaction.
Журнал: JOURNAL OF CHROMATOGRAPHIC SCIENCE
Выпуск журнала: Vol. 54, Is. 7
Номера страниц: 1253-1262
ISSN журнала: 00219665
Место издания: CARY
Издатель: OXFORD UNIV PRESS INC