Isotope dilution thermal ionization mass spectrometry (ID-TIMS) for determination of concentration of enriched lithium using NaLiBO2+ ions

High-Precision Measurement of the 238Pu/239Pu Isotope Ratio by TIMS

“…This compound is then calibrated using synthetic mixtures containing varying isotope abundance, achieved by gravimetrically mixing calculated proportions of highly enriched isotopes of the element. Then, for a given TIMS methodology, the mass discrimination correction factor K is calculated using the iterative approach. − In the 1970s, the National Bureau of Standards (NBS) certified isotopic standards using this method with state-of-the-art instruments available at that period . However, advancements in instrumentation now yield within-run precision lower than certified uncertainties.…”

“…However, advancements in instrumentation now yield within-run precision lower than certified uncertainties. In addition, there is better understanding of the uncertainty budget estimation of the adopted analytical methodology prescribed by the JCGM (Joint Committee for Guides in Metrology) GUM (Guide to the Expression of Uncertainty in Measurement)-6:2020, and due to the exhaustion of the prepared isotopic standard, the practice of recertification of the isotopic standards is often being followed. ,− Notably, the total evaporation and ion integration methodology for the isotope ratio of lithium, in lithium isotopic standard (NIST-RM 8545), using NaLiBO 2 + ions has been demonstrated in our laboratory to show close agreement with the recertified value …”