Electroanalytical and isothermal calorimetric study of As(III) complexation by the metal poisoning remediators, 2,3-dimercapto-1-propanesulfonate and meso-2,3-dimercaptosuccinic acid

A recently developed methodology, which combines voltammetry, ITC, ESI-MS and several chemometric tools, has been applied for the first time to the study of As(III) complexes. The ligands considered, DMSA and DMPS, are commonly used to treat heavy metal poisoning. The study yields a reliable and consistent picture of the binding of As(III) by the chelating therapy agents DMSA and DMPS providing an unambiguous description of the stoichiometries of the complexes (ML2, with the occasional appearance of ML in the case of DMSA), both ligands have stability constants of the same order, with a log β2 of 9.2 and 9.8, respectively. These values confirm the potential efficiency of both ligands in the treatment of As(III) poisoning.

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► A voltammetric approach is applied to the study of As(III) complexation by poisoning remediators.
► Voltammetry measurements are complemented with Isothermal Titration Calorimetry (ITC) and Electrospray Ionization Mass Spectrometry (ESI-MS).
► Voltammetric data are analyzed by Gaussian Peak Adjustment (GPA) method.