SURFACTANT ION-SELECTIVE MEMBRANE ELECTRODES

Calix[8]arene ethers, carboxylic esters having various p-substituents and acid are synthesized and studied. In a bulk membrane transport of dodecylpyridinium the better carrier is the simplest host, calix[8]are ne octamethyl ether. Inversely, it is the worst carrier for dodecyltri methylammonium; the better here is carboxy ester with adamantyl p-subs tituents. Various calixarenes are successfully used in plasticized mem brane ion-selective electrodes (ISE) for both above ammonium and pyrid inium surfactants. Operational characteristics, potentiometric selecti vity and optimal membrane compositions are reported. Typical limit of detection is at the level of nx 10(-6) - 1 x 10(-5) M, response time 5 - 10 s, and lifetime is at least 6 months. ISE's selectivity is signi ficantly better than that of ion-association and crown-ether based ele ctrodes.