The Ca(2+)-EDTA chelation as standard reaction to validate Isothermal Titration Calorimeter measurements (ITC)

Clara Ràfols; Elisabeth Bosch; Rafael Barbas; Rafel Prohens

doi:10.1016/j.talanta.2016.03.075

The Ca(2+)-EDTA chelation as standard reaction to validate Isothermal Titration Calorimeter measurements (ITC)

Talanta. 2016 Jul 1:154:354-9. doi: 10.1016/j.talanta.2016.03.075. Epub 2016 Mar 25.

Authors

Clara Ràfols¹, Elisabeth Bosch², Rafael Barbas³, Rafel Prohens³

Affiliations

¹ Departament de Química Analítica i Institut de Biomedicina (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain. Electronic address: crafols@ub.edu.
² Departament de Química Analítica i Institut de Biomedicina (IBUB), Universitat de Barcelona, Martí i Franquès 1-11, 08028 Barcelona, Spain.
³ Unitat de Polimorfisme i Calorimetria, Centres Científics i Tecnològics, Universitat de Barcelona, Baldiri Reixac 10, 08028 Barcelona, Spain.

PMID: 27154686
DOI: 10.1016/j.talanta.2016.03.075

Abstract

A study about the suitability of the chelation reaction of Ca(2+)with ethylenediaminetetraacetic acid (EDTA) as a validation standard for Isothermal Titration Calorimeter measurements has been performed exploring the common experimental variables (buffer, pH, ionic strength and temperature). Results obtained in a variety of experimental conditions have been amended according to the side reactions involved in the main process and to the experimental ionic strength and, finally, validated by contrast with the potentiometric reference values. It is demonstrated that the chelation reaction performed in acetate buffer 0.1M and 25°C shows accurate and precise results and it is robust enough to be adopted as a standard calibration process.

Keywords: Energetics of Ca(2+)–EDTA chelation; ITC; ITC chemical calibration; ITC measurements validation; Isothermal Titration Calorimeter.

Publication types

Research Support, Non-U.S. Gov't