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

Abstract

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.