A chalcohalide glass/alloy based Ag+ ion - selective electrode with nanomolar detection limit

In this paper, a silver ion-selective electrode material with lower detection limit is presented. The electrode is based on 22.5As(2)S(3)-22.5Ag(2)S-55AgCl chalcohalide glass membranes. The low detection limit decreases from the micromolar range of the original Ag2S-As2S3 electrode to the nanomolar level (1.89 nM) by introducing AgCl. The addition of AgCl increases the conductivity of the glasses and improves the analytical properties of electrodes because of the joint effects of Ag+ and Cl- on network structure of the glass. The super-Nernstian response behavior was observed for the partially crystallized electrode. The electrode containing AgCl also possesses a high selectivity (except for Hg2+), fast response and good stability.