Silver(I)-selective membrane electrode based on hexathia-18-crown-6

Abstract

A PVC membrane electrode for Ag+ ions based on hexathia-18-crown-6 as membrane carrier was prepared. The sensor exhibits a Nernstian response for silver ions over a wide concentration range (3.2 x 10-3 - 6.0 x 10-6 M) with a slope of 59 mV decade-1. The limit of detection is 4.0 x 10-6 M (0.43 μg ml-1). It has a response time of < 10 s and can be used for at least three months without any divergence in potential. The proposed electrode shows fairly a good discriminating ability towards Ag+ ion in comparison to some alkali, alkaline earth, transition and heavy metal ions. The electrode can be used in the pH range from 2.0 to 7.5. It was used as an indicator electrode in potentiometric titration of silver ion.