Detection of surface aggregates of trace amounts of copper and silver on graphite using secondary ion mass spectrometry at elevated temperatures. Invited lecture

Abstract

Static secondary ion mass spectrometry is used to investigate the extent of dispersion of copper and silver on a pyrolytic graphite coated graphite surface. The appearance of secondary fragment ions consisting of more than one atom of the metal analyte is used as an indication that the sample is present on the surface as aggregates. This signal for the polymeric metal ion is compared with the signal for the monatomic fragment ion for various concentrations. Concentration studies were conducted for both metals, and copper was found to exist as dispersed copper species at lower concentrations while at higher concentrations evidence suggests surface aggregates or microdroplets. Silver was found to exist as aggregates for the range of concentrations studied.