Pb2+ potentiometric chemical sensors based on lead and silver doped thioaresenate glasses

Abstract

Lead doped chalcogenide glass compositions, in the pseudo-ternary AgI-PbS-As2S3, were examined as active membrane materials for the construction of Pb(II) ion-selective sensors, Pb(II)−ISE. The basic glass properties of the synthesised bulk samples such as vitreous state, macroscopic, thermal and electric properties were studied. To this end, several techniques were used, including X-ray powder diffraction, density measurements, differential scanning calorimetry, scanning electron microscopy and impedance complex spectroscopy. It is found that the density increases with increased AgI and PbS contents. The glass transition temperatures for the studied compositions were also reported. The electrical measurement show the conductivity increases with increasing AgI content. Meanwhile, for the glasses with same AgI content and increasing PbS content, the conductivity decreases. For the fabricated sensors, several key analytical parameters were investigated to evaluate the different glass compositions as active membranes in Pb(II)−ISE, including detection limit, sensitivity, linearity, ionic selectivity (in the presence of K+, Na+, Ni2+, Ca2+, Cd2+, Cu2+ and Hg2+ interfering cations), reproducibility and optimal pH-range.