Silver ion-selective electrodes employing Schiff base p-tert-butyl calix[4]arene derivatives as neutral carriers

The potentiometric response characteristics and selectivity properties of poly(vinylchloride) (PVC) matrix membrane ion-selective electrodes for silver(I) ion, based on Schiff base p-tert-butyl calix[4]arene derivatives containing N and O as binding sites, were examined. These derivatives proves to work well with silver ions and corresponding electrodes display an excellent response to this ion. These electrodes works well over wide range of concentration (1.0 x 10(-5) to 1.0 x 10(-1) M) with a Nernstian slope. The electrodes have a fast response time of 20 s and operates in the wide pH range. These calix[4]arene derivatives, each showed excellent selectivities in ISE membrane electrodes with log K-Ag,M(pot) around -4.5 against some of the alkali, alkaline and transition metals, even against the strongest interferent, Hg2+ ions, the value was around -3.0. These silver(I) ion-selective electrodes were used as an indicator electrode for potentiometric titration of silver(l) using standard solution of sodium chloride, a sharp potential change occur at the end point. These ISEs were also used to determine low concentration of silver(I) ion in partially non-aqueous medium. (C) 2003 Elsevier Science B.V. All rights reserved.