Silver bromide based chalcogenide glassy-crystalline ion-selective electrodes

Abstract

The response of bromide ion-selective electrodes based on chalcogenide glassy-crystalline AgBr-Ag₂S -As₂S₃ alloys is described. The analytical characteristics of these sensors were superior to those of conventional crystalline AgBr-Ag₂S and AgBr membrane electrodes in the range of Nernstian response and resistance to acids, strong oxidising agents and corrosive media. These latter features of the electrode response were useful for the application of glassy-crystalline bromide ion sensors to the study of Belousov-Zhabotinsky oscillatory reactions. Vitreous chalcogenide sensors displayed no bromide ion response. Radioactive-tracer measurements revealed that there was no exchange of ⁸²Br between the solution and glasses whereas this phenomenon was observed to occur for single-crystal AgBr and glassy-crystalline alloys. The results were in good agreement with an X-ray photoelectron spectroscopic study of the membrane surface.