CESIUM-SELECTIVE POLY (VINYLCHLORIDE) MEMBRANE ELECTRODE BASED ON A NEW CALIX[4]ARENE DERIVATIVE IN THE 1,3-ALTERNATE CONFORMATION

Abstract

ABSTRACT A new calix[4]arene derivative [25-(3-bromo-propyloxy)-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 × 10−6–1.0 × 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 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 × 10−7 M) and improved Cs+/Rb+ selectivity in comparison with the previously reported Cs+ ion selective electrodes.