Understanding how environmental conditions may affect sample composition is critical to the interpretation of laboratory analyses
from environmental sampling. We prepared a set of UO2F2 particle samples from the hydrolysis of UF6 and stored these samples in environmental chambers at different temperature, humidity and lighting conditions. The NanoSIMS
ion microprobe was used to measure the UF+/U+ secondary ion ratio of individual particles. Monitoring variations in this ratio may provide insights on changes in particle
composition over time and in response to environmental exposure. This report presents the baseline measurements carried out
on freshly-prepared particle samples to determine the initial amount of fluorine.