USE OF A INOPHORETIC TECHNIQUE IN THE STUDY OF MIXED-LIGAND COMPLEXES OF Mn(II) AND Pb(II) WITH ADENOSINE MONOPHOSPHATE AND NITRILOTRIACETATE

Abstract

A new method, paper electrophoresis, involving the use of a ionophoretic technique is described for the study of equilibria in mixed-ligand systems in solution. The migration of a metal ion spot (M), under an electric field with complexants added in the background electrolyte at the fixed pH 8.5 is studied. For the study of ternary complexes, the concentration of the primary ligand, adenosine monophosphate (AMP), is kept constant while that of the secondary ligand, nitrilotriacetate (NTA), is varied. Plots of log [NTA] against mobility provided information about the mixed-ligand complex allowing calculation of the stability constants. As a prerequisite, the binary equilibria of M(II)-AMP and M(II)-NTA have also been studied. The overall stability constants (log K) of the M(II)-AMP-NTA complexes have been found to be 7.31 and 8.25 for the Mn(II) and Pb(II) complexes, respectively, at u = 0.1 and at 30 ± 0.1 °C