Time-of-flight static secondary ion mass spectrometry analysis of surface contamination on Pt/Ir standard mass material

Static time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been used to characterize surface contaminants on a Pt-10% Ir alloy sample prescribed for fabrication of a prototype kilogram mass standard. The identification of various oxygenated and non-oxygenated hydrocarbon adsorbates on the Pt-Ir surface provides a scenario for the increase in mass observed after standard cleaning procedures, and as a function of time. Static TOF-SIMS analysis suggests the catalytic activity of Pt plays a key role in the adsorption of organic solvents used in standard cleaning procedures as well as adsorption of hydrocarbon species present in ambient laboratory air.