Bis Crown Ethers( Ⅸ)——Caesium Selective PVC Membrane Electrodes Based on Schif f Base Type of Bis Crown Ethers

Recently, much attention has been focused on the use of neutral carrier species as membrane components to extract ions from aqueous solution into a hydrophobic membrane phase. Some potassium-or caesium-selective electrodes based on bis-benzo-15-crown-5 or bis-benzo-18-crown-6 containing ester or other linkage were prepared by K. Kimura and K. W. Fung. The selective coefficients K_(K,Na)~(pot), K_(Cs,Na)~(pot),or K_(Cs,K)~(pot), K were 2.6×10~(-4), 1.9×10~(-2) and 1.7×10~(-1), respectively.