Comparison of the selectivity of propeller crowns in poly(vinyl chloride) membrane ion-selective electrodes

Abstract

The selectivity of poly(vinyl chloride) membrane ion-selective electrodes containing propeller crowns for K⁺ or Rb⁺ over Na⁺ has been measured. Propeller crowns with six oxygen donors are selective for K⁺ over Na⁺ by a factor of 10^–2–10^–3; those with seven oxygen donors are selective for Rb⁺ over Na⁺. The trends in selectivity are correlated with propeller mobility, as assessed by nuclear magnetic resonance spectroscopic methods, and with ability to transport cations in three-phase systems.