Cesium-selective poly(vinylchloride) membrane electrode based on a new calix[4]arene derivative in the 1,3-alternate conformation

A new calix[4]arene derivative [25-(3-bromo-proploxy)-5,11,-17,23-tetrakis(tert-butyl)-26,27,28-tris(1-propyloxy) calix[4]arene] (BTC) in the 1,3-alternate conformation was tested as a cesium-selective ionophore plasticized PVC membrane electrode. The resulting electrode showed a Nernstian behavior for Cs(+) ion over a wide concentration range (1.0 x 10(-6)-1.0 X 10(-1) M). The selectivity coefficients for cesium with respect to alkali, alkaline earth, ammonium and some transition metal ions, were determined. A relatively high Cs(+)/Rb(+) selectivity was observed, the selectivity coefficient (K(Cs, Rb)(pot)) being ca. 10(-2). Effects of membrane composition and pH of test solution on the potential response of the electrode were also discussed. The proposed electrode revealed a lower limit of detection (2.1 x 10(-7) M) and improved Cs(+)/Rb(+) selectivity in comparison with the previously reported Cs(+) ion selective electrodes.