Thermodynamic interactions of the alkaline earth metal ions with citric acid
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By using the isothermal titration calorimetry (ITC) technique, thermodynamic parameters have been determined for reactions of the Mg2+, Ca2+, Sr2+, and Ba2+ ions with the citrate anion. The measurements were run in the Cacodylate, Pipes and Mes buffer solutions of a pH of 6, at 298.15 K, as well as in the Tricine, Tapso, and Tris–HCl buffer solutions of a pH of 8. Further, based on the results of potentiometric titration, the conditional stability constants were determined for the citrate complexes at both pH values. The effect of the reaction environment and the metal ion identity on the interaction energy with the citrate ligand and the stability of the resulting compounds have been discussed.
KeywordsCitrate complexes Thermodynamic parameters Isothermal titration calorimetry
This research was supported by the Polish Ministry of Science and Higher Education under Grant DS/8230-4-0088-10.
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