Direct Uranium Isotopic Analysis of Environmental Swipes using Microextraction- LS-APGD/Orbitrap-FTMS Booster

Environmental swipe sampling is an integral component of the International Atomic Energy Agency’s (IAEA) nuclear safeguards monitoring program. Samples are routinely collected and analyzed from nuclear facilities to ensure compliance with the declared nuclear materials and activities and to identify any undeclared materials. The time taken from swipe collection to analytical findings is critical, with rapid turnaround and reliable results being of paramount importance. However, current workflows for isotopic analysis are time intensive, often requiring weeks to months. Furthermore, prior chemical separations are required due to the limited mass resolution of current commercial mass spectrometers, further prolonging the time to analysis. Presented is an integrated approach that drastically reduces the analysis time to minutes without compromising analytical performance. Both the front end (sample introduction to ionization) and the back end (mass analysis) are taken into consideration for rapid turnaround. Sample particulates/residues are directly extracted from cotton swipes using a microextraction platform without the need for any other sample preparation. The extracted materials are ionized in a highly efficient liquid sampling-atmospheric pressure glow discharge (LS-APGD) ionization source. The ultrahigh mass resolution of the Orbitrap mass spectrometer, further enhanced by the FTMS-Booster, enables separation of the vast majority of isobaric interferences, eliminating the need for time-consuming and laborious chemical separation. Optimization of important microextraction parameters, such as extraction force and time, along with plasma operating parameters for U isotope ratio analysis from swipes, will be discussed. The system’s capability for isotopic analysis in the presence of excess interfering elements will be demonstrated. Finally, findings from the analysis of some swipe samples taken from various laboratory equipment surfaces/locations will be presented.