PNNL

Abstract

To address the need for rapid, high-throughput actinide isotopic analysis in nuclear forensics, environmental monitoring, and geochemical research, we present an automated microchemical separation workflow using a repurposed Hamilton MicroLab liquid handler together with a Neoma MS/MS multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS). Custom 3D-printed columns were used with various extraction resins under positive pressure to enable rapid microdissolution and chemical purification of uranium, plutonium, neptunium, and americium from various standard reference materials. Automated chromatographic separations yielded actinide recoveries of 3-68% for U and 47-110% for Pu, slightly lower than those obtained by manual chemistry, which produced U recoveries of 30-80% and Pu recoveries of 81-96%, but still maintained isotopic accuracy within 1% of certified values for all measured isotopes. Dissolution experiments produced U recoveries ranging from 0.05% to 111%. The complete workflow from sample dissolution through purification and MC-ICP-MS analysis was completed in less than 4 hours, which is 4 times faster compared to the multiple days required by traditional manual methods. We find that the automated microchemistry approach does not compromise measurement precision or accuracy, as demonstrated by replicate analyses of reference materials spanning a range of actinide compositions and isotopic signatures. Our results demonstrate that this automated platform maintains the selectivity and efficiency required for high-precision isotopic measurements while significantly improving sample throughput. This approach has potential for time-sensitive applications requiring rapid actinide analysis, including nuclear safeguards verification and rapid environmental assessment.