Formation and Stability of Cadmium(II)/Phytate Complexes by Different Electrochemical Techniques. Critical Analysis of Results
- Authors: De Stefano, C; Lando, G; Milea, D; Pettignano, A; Sammartano, S
- Publication year: 2010
- Type: Articolo in rivista (Articolo in rivista)
- OA Link: http://hdl.handle.net/10447/49041
Abstract
In the present work the stability constants of various cadmium(II)/phytate (Phy) species were determined at T = 298.15 K in NaNO3(aq) at I = 0.1 mol·L−1 by DP-ASV (Differential Pulse Anodic Stripping Voltammetry) and by potentiometric titrations using an ISE-Cd2+. Cyclic voltammograms were also recorded to check the electrochemical behavior of cadmium in the presence of phytate. The results were analyzed together with previous data determined by ISE-H+ measurements. Data obtained were used to provide an exhaustive speciation scheme for the phytate/cadmium(II) system at different conditions, as well as a comprehensive representation of the binding ability of phytate toward cadmium(II). Different pL50 values {a previously proposed empirical parameter, expressed as −log10 CPhy, where CPhy is the total phytate concentration necessary to bind 50% cadmium(II)} were also calculated by modeling its dependence on pH.