Alkali and alkaline earth metal-ion adducts of poly(propylene glycol) as sensors for ion-selective electrodes

Abstract

Tetraphenylborates (TPBs) of sodium and alkaline earth metal-ion complexes with a poly(propylene glycol)[PPG(1025)] have been evaluated for their ion-selective electrode qualities in conjunction with 4-nitroethylbenzene, 2-nitrophenyl phenyl ether, tributyl phosphate, dioctyl phenylphosphonate and dioctyl 3-nitrophenylphosphonate as solvent mediators. A good PVC matrix-membrane calcium ion-selective electrode functional over a wide pH range (4.5– > 10) is based on PPG(1025).Ca.2TPB sensor and dioctyl phenylphosphonate solvent mediator. Anions such as nitrate, thiocyanate and perchlorate do not interfere with electrode calibrations as they do with certain other electrodes based on neutral carrier sensors.