Ion-selective membrane electrodes based on ion-pair complexes: Correlations between slope of electrodes and stability of ion-pair complexes

A theoretical function model and four correlation equations between slope of electrode, and parameters such as: log beta(s) (where beta(s) is the stability constant of ion-pair complex), dipole moment (CL), molecular refraction coefficient (n(D)(20)), plasticizer polarity (epsilon(r)), and partition coefficient of various ions between solution and membrane (k) are proposed for the ion-selective membrane electrodes based on ion-pair complexes. It is possible to model the ion-selective membrane electrodes' slopes through the stability constant of the ion-pair complexes, even if this value is not accessible, through some parameters of the medium: mu, n(D)(20) for solvents whereas, for the membrane plasticizer, the parameters are epsilon(r) and k.