Surfactant Ion Selective Membrane Electrodes

Abstract

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]arene octamethyl ether. Inversely, it is the worst carrier for dodecyltrimethylammonium; the better here is carboxy ester with adamantyl p-substituents. Various calixarenes are successfully used in plasticized membrane ion-selective electrodes (ISE) for both above ammonium and pyridinium surfactants. Operational characteristics, potentiometric selectivity and optimal membrane compositions are reported. Typical limit of detection is at the level of nx10⁻⁶ - 1x10⁻⁵ M, response time 5-10 s, and lifetime is at least 6 months. ISE's selectivity is significantly better than that of ion-association and crown-ether based electrodes.

Key Words:

• PVC membrane
• calix[8]arene
• ion-selective electrode
• cationic surfactant
• transport.