Silver(I) ion-selective membrane based on Schiff base-p-tert-butylcalix[4]arene

A PVC membrane electrode for silver(I) ion based on Schiff base-p-tert-buty lcalix[4]arene is reported. The electrode works well over a wide range of c oncentration (1.0 x 10(-5)-1.0 x 10(-1) mol dm(-3)) with a Nernstian slope of 59.7 mV per decade. The electrode shows a fast response time of 20 s and operates in the pH range 1.0-5.6. The sensor can be used for more than 6 m onths without any divergence in the potential. The selectivity of the elect rode was studied and it was found that the electrode exhibits good selectiv ity for silver ion over some alkali, alkaline earth and transition metal io ns. The silver ion-selective electrode was used as an indicator electrode f or the potentiometric titration of silver ion in solution using a standard solution of sodium chloride; a sharp potential change occurs at the end-poi nt. The applicability of the sensor to silver(I) ion measurement in water s amples spiked with silver nitrate is illustrated.