Effect of Plasticizer on the Selectivity of Potassium-selective PVC Membrane Electrodes Based on Bis(crown ether)s

Potassium-selective PVC membrane electrodes based on bis(crown ether)s containing benzo-15-crown-5 moiety were prepared, o-nitrophenyl octyl ether (NPOE) or dipentyl phthalate (DPP) being used as a plasticizer. Selectivity coefficients for various monovalent ions were measured. The preference of potassium over sodium in the bis(crown ether) (I; n=5)–NPOE electrode system is close to that in the valinomycin system.