Determination of the surface composition of lead electrode membranes by electron spectroscopy for chemical analysis

Abstract

The interfaces between an ion selective electrode (ISE) membrane and the internal reference solution and external analyte solution are important in the overall response of solid-state ion-selective electrodes. Since the surface composition of a solid may differ from the bulk composition, we have used electron spectroscopy for chemical analysis (ESCA) in order to characterize the surfaces of lead ion selective electrode membranes. Both untreated and solution-exposed membranes have been studied. From the latter, evidence for the hydration of the outermost monolayers of the membrane has been obtained. This implies that ion exchange processes are viable and may be an important factor in the overall response of solid-state membrane electrodes. Finally, the effectiveness of the use of EDTA and HClO/sub 4/ as cleaning agents for the membrane has been correlated with changes in the membrane surface composition.