STP1291: Determination of the Concentration and Isotopic Composition of Uranium in Environmental Air Filters

    Russ, GP
    Chemist, Lawrence Livermore National Laboratory, Livermore, CA

    Bazan, JM
    Chemist, Lawrence Livermore National Laboratory, Livermore, CA

    Pages: 10    Published: Jan 1995


    Abstract

    For many years, Lawrence Livermore National Laboratory has collected monthly air-particulate filter samples from a variety of environmental monitoring stations on and off site. Historically, the concentration and isotopic composition of uranium collected on these filters were determined by isotope dilution using a 233U spike and thermal ionization mass spectrometry (TIMS). For samples containing as little as 10 ng of uranium, ICP-MS is now used to make these measurements to the required level of precision, 5% in the measured 235/238 and 233/238. Unless particular care is taken to control bias in the mass filter, variable mass bias limits accuracy to a few percent. Measurements of the minor isotopes 236 (if present) and 234 are also possible and provide useful information for identifying the source of the uranium. The advantage of ICP-MS is in rapid analysis, ≈12 min of instrument time per sample.

    Keywords:

    uranium, ICP-MS, isotopic ratio measurements, air filters, environmental monitoring


    Paper ID: STP15985S

    Committee/Subcommittee: C26.05

    DOI: 10.1520/STP15985S


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