Sodium-selective membrane electrode based on p-tert-butylcalix[4]arene methoxyethylester

Twelve calixarenes have been studied as prospective ionophores for sodium. Five of these have shown promising results in the liquid membrane form. All five have been successfully incorporated into poly(vinyl chloride) membranes, and applied as ion-selective electrodes for sodium. Electrode responses, selectivities towards alkali and alkaline earth metals as well as towards hydrogen and ammonium ions, temperature coefficients and response times have been studied. Based on these results p-tert-butylcalix[4]arene methoxyethylester has been chosen as the best ionophore for the preparation of sodium-selective electrodes. Details of electrode construction are presented.