CATALYSIS OF ION TRANSFER BY TETRAPHENYLBORATES IN NEUTRAL CARRIER-BASED ION-SELECTIVE ELECTRODES

For certain ionophores of extremely high lipophilicity, kinetic limitations of the carrier‐induced ion transfer between aqueous and membrane phase may heavily disturb the electromotive behaviour of the ion‐selective membrane electrode. These limitations may be overcome by adding tetraphenylborates to the membrane phase. Membranes prepared with different 3,6‐dioxaoctanediamide homologues and potassium tetrakis(P‐chlorophenyl)borate as phase‐transfer catalyst all exhibit the same ion selectivity as well as theoretical electrode response. This behaviour is corroborated by a theoretical description of the ion‐transfer process. Copyright © 1990 Verlag GmbH & Co. KGaA, Weinheim