Direct uranium isotope ratio analysis of single micrometer-sized glass particles

► LA-MC-ICP-MS was fully validated for the direct analysis of individual particles. ► Traceability was established by using an IRMM glass particle reference material. ► Measured U isotope ratios were in agreement with the certified range. ► A comprehensive total combined uncertainty evaluation was performed. ► The analysis of 236U/238U isotope ratios was improved by using a deceleration filter.