Binding constant determination of uranyl–citrate complex by ACE using a multi‐injection method

Abstract

The binding constant determination of uranyl with small-molecule ligands such as citric acid could provide fundamental knowledge for a better understanding of the study of uranyl complexation, which is of considerable importance for multiple purposes. In this work, the binding constant of uranyl-citrate complex was determined by ACE. Besides the common single-injection method, a multi-injection method to measure the electrophoretic mobility was also applied. The BGEs used contained HClO4 and NaClO4 , with a pH of 1.98 ± 0.02 and ionic strength of 0.050 mol/L, then citric acid was added to reach different concentrations. The electrophoretic mobilities of the uranyl-citrate complex measured by both of the two methods were consistent, and then the binding constant was calculated by nonlinear fitting assuming that the reaction had a 1:1 stoichiometry and the complex was [(UO2 )(Cit)](-) . The binding constant obtained by the multi-injection method was log K = 9.68 ± 0.07, and that obtained by the single-injection method was log K = 9.73 ± 0.02. The results provided additional knowledge of the uranyl-citrate system, and they demonstrated that compared with other methods, ACE using the multi-injection method could be an efficient, fast, and simple way to determine electrophoretic mobilities and to calculate binding constants.

Study on the interaction of uranyl with sulfated beta‐cyclodextrin by affinity capillary electrophoresis and molecular dynamics simulation

“…It attracts attentions due to a number of advantages, including high separation efficiency, rapid analysis, power saving, minimal sample consumption and easy for automation . In recent years, several studies focused on the determination of binding constants of uranyl with a variety of ligands by means of ACE have been reported , for instance, the carboxylic acids (acetate , oxalate and citrate ), inorganic anions (iodate and selenate ) and proteins . Considering that uranyl is one of kinetically fast metals and tends to form labile complexes unless being coordinated by strong chelators , the ACE method is very suitable for study the interaction of uranyl with S‐β‐CD in aqueous solution.…”

Affinity capillary electrophoresis in studying the complex formation equilibria of radionuclides in aqueous solutions

“…The ACE has recently been used to determine the stability constants of uranyl citrate complex and a number of actinide oxalate complexes . The more detailed information on stability constant determination of metal and actinide ions with diverse ligands obtained by ACE can be also found in recent reviews .…”

Using open‐tubular capillary electrochromatography with part‐coating column for binding constants determination of β2‐adrenergic receptor with seven drugs

“…Thus, the determination of binding constants has considerable importance. There are number of techniques to measure binding constants, such as enzyme immunoassay , titration , CZE , ACE , nuclear magnetic resonance , fluorescence spectroscopy , and surface plasmon resonance biosensor technology , etc. Besides the general methods, ultrasonic microdialysis coupled with online capillary electrophoresis electrochemiluminescence , acoustic wave sensor devices , and near‐infrared dye‐displacement capillary electrophoresis were also used to determine binding constants.…”