Design features of ionophores for ion selective electrodes

Abstract

Ionophores as components for analytically relevant ion selective electrodes have to exhibit a specified lipophilicity and a free energy of activation of < 45–65 kJ mol-1 for the ligand exchange reaction. The selectivity of membranes may be tuned by membrane-technological interventions (dielectric constant of membrane phase, ionophore concentration, concentration of ionic sites confined to membrane phase). Molecular modelling techniques can guide the design of ionophores of a given inherent selectivity and reduce the number of ionophore candidates to be synthesized. The selectivity enhancement expected for a covalent link of ionophore subunits is analyzed. Significant effects are predicted only if suitable ligand preorganization is realized. © 1988 IUPAC