Equilibrium Studies of Cobalt (II) and Copper (II) with Diethylene Triamine Penta Acetic Acid (DTPA)

Biologically important complexes involving DTPA have been investigated potentiometrically in aqueous medium under the well-defined condition of temperature and ionic strength. SCOGS computer program is used to obtain the speciation of various protonated, nonprotonated binary and ternary species formed in a particular equilibrium. The percentage formation of complexes is appreciably high which is evident from speciation curves. The stability constants and thermodynamic parameters G, H, and S support the favourable formation of mixed metal species. Negative values of logK indicates higher stability of ternary species.