Chalcogenide glass-based sulphide sensor in thick film technology

The fabrication and characterisation of potentiometric chalcogenide glass (CG) electrodes with selectivity for sulphide in aqueous media are reported, with the focus of the work being on the thick film (TF) technique as the fabrication technology. In contrast to the results of recently completed investigations to create electrodes that are also CG-based and selective for other anions (e.g. for the determination of iodide), it has been possible to achieve planar ion-selective electrodes (ISE) that are stable over the longer term while retaining the amorphousness of the electrode membrane material using the above-mentioned manufacturing method. Thermal decomposition behaviour in the sintered area of the glasses, which would have made processing into a glass paste and its screen printing and firing onto a ceramic substrate to produce a dense glass membrane using the TF process impossible, could not be determined here. In addition to the fabrication processes for the CGs and the pastes, their investigation by means of various physico-chemical methods, the fabrication into usable sensors and their testing are described in comparison with commercially available electrodes selective for sulphide ions based on Ag2S compacts.