Mechanisms of the origins of membrane potentials for pseudo-liquid poly(vinyl chloride) matrix membranes incorporating coordinatively solvated complexes

Abstract

Studies on the mechanism of the electrode potential produced by pseudo-liquid poly(vinyl chloride)(30%) matrix membranes incorporting a calcium nitrate–tributyl phosphate coordinatively solvated complex (70%) are reported. It was found that the character (cationic or anionic) of the electrode function was dependent on the concentration of the complex in the membrane phase but the formation of the membrane potential in the aqueous phase concentration range Ca(NO₃)₂ > 0.1 mol l^–1 depended on the extraction process. The concept of using the potentiometric data characterizing the surface layer of a pseudo-liquid membrane phase for the determination of extraction distribution coefficients is presented. The semi-empirical dependence describing the electrode potential in Ca(NO₃)₂ solutions of concentrations greater than 0.1 mol l^–1 is discussed.