Chalcogenide Glass Based Heavy Metal Sensors

A number of chalcogenide glasses for the fabrication of potentiometric electrodes selective for heavy metal ions were melted and characterised. The focus was directed on the detection of Cu2+ and Pb2+ ions. Until now, for measurements, only rod electrodes were available. In addition to the preparation of conventional rod electrodes, the purpose of the research was the realisation of corresponding planar electrodes in thick film technology. Therefore, the bulk material of the chalcogenide glasses was milled to glass powder and the sintering behaviour of the glasses was investigated. Non-crystallising, densely sintered glasses were processed into thick film pastes for the deposition of heavy metal ion selective chalcogenide glass membranes on a ceramic substrate. Miniaturised electrodes were achieved for the case of copper ion determination, whereupon several glass compositions were tested. The sintering behaviour of the investigated lead ion selective glasses did not allow the fabrication of an ion selective electrode by the thick film process. The requirement to add AgI to the initial mix is associated with light sensitivity of corresponding sensors.