Cesium selective electrodes based on novel double flexible spacers bridged biscalix[4]arenes

Two novel double flexible spacers brideged biscalix[4]arenes 25,25',27.,27'-bis(1,3-dioxypropane)-bis(5,11,17,23-p-tert-tetrabutylcalix[4]arene-26,28-diol) (1) and 25,25',27,27'-bis(1,4-dioxybutane)-bis(5,11,17,23-p-tert-tetrabutylcalix[4]arene-26,28-diol) (2) have been evaluated as cesium ion-selective ionophore in polymeric membrane electrodes. The electrodes all give the good Nernstian response of 51 mV per decade for Cs+ in the concentration range from 1 x 10(-1) to 1 x 10(-5) M and good selectivity. The potentiometric selectivity of Cs+-ISEs based on 1 and 2 for cesium ion over other alkali metal ions, alkaline-earth metal ions and NH4+ have been assessed. Effects of membrane composition and pH on the response of Cs+-ISEs based on 1 and 2 were also discussed. (C) 2001 Elsevier Science B.V. All rights reserved.