A cobalt(II)-selective PVC membrane based on a Schiff base complex of N,N′-bis(salicylidene)-3,4-diaminotoluene

A new PVC membrane electrode for Co2+ based on N,N'-bis(salicylidene)-3,4-diaminotoluene, an excellent neutral carrier, has been fabricated using sodium tetraphenylborate (NaTPB) as an anionic excluder and dioctylphthalte (DOP) as a solvent mediator. The electrode exhibits a linear potential response in the concentration range of 7.9 x 10(-8) to 1.0 x 10(-1) M with a slope of 30 +/- 0.2 mV per decade. The detection limit of the proposed sensor is 5.0 x 10(-8) M and it can be used over a period of 5 months. The proposed sensor revealed good selectivity over a wide variety of other cations including alkali, alkaline earth, heavy and transition metals and could be used in the pH range of 2.0-9.0. This electrode was successfully applied for the determination of Co2+ in real samples and as an indicator electrode in potentiometric titration of cobalt ions. (c) 2006 Elsevier B.V. All rights reserved.