Dicyclohexano-18-crown-6 as active material in PVC matrix membrane for the fabrication of cadmium selective potentiometric sensor

PVC based membrane containing dicyclohexano-18-crown-6 (1) as active material along with sodium tetraphenyl borate (NaTPB) as an anion excluder and dibutyl phthalate as solvent mediator in the ratio 20:4:150:150 (w/w) (I-NaTPB-DBP-PVC) exhibits good properties with a Nernstian response of 29.0 +/- 1.0 mV per decade of activity and a working concentration range of 2.1 x 10(-5)-1.0 x 10(-1). The working PH range of the sensor is 1.9-7.0. It exhibits a fast response time as fast as 17 s and has a lifetime of about 6 months. The proposed sensor has good selectivity for cadmium over alkali, alkaline earth, some transition and heavy metal ions. The sensor works satisfactorily in mixtures having 10% (v/v) non-aqueous content without showing any considerable change in working concentration range or slope. It has been successfully used as an indicator electrode for the potentiometric titration of Cd2+ against EDTA as well as for its determination in wastewaters. (C) 2002 Published by Elsevier Science Ltd.