Abstract
The use of sensors to monitor gaseous species in various processes is discussed. Most solid electrolyte sensors that are used in gases involve electrolytes which conduct the ion of the species to be measured. However, this is not possible for sulphur and nitrogen and in order to overcome this problem, cation conducting electrolytes have been synthesised which respond to nitrogen and sulphur. For gases containing two elements, novel sensors, based upon two electrolytes, have been developed, whose potential in a multicomponent gas mixture is independent of the oxygen content and do not require high temperature gas seals or separate references.