ASTM C1844-16

1.1 This test method covers the determination of uranium in urine by Inductively Coupled Plasma Mass Spectrometry (ICP-MS) after dilution in nitric acid. The method is presented in two parts. Part A describes a method for determination of total uranium in urine that does not distinguish between uranium isotopes. Part B describes a method that determines the ratio of ²³⁵U to ²³⁸U (the enrichment) in samples that Part A has shown to contain levels of uranium that the user of the data considers to be significant. The measurement in Part B may be combined with the measurement in Part A to calculate a ²³⁵U concentration. The enrichment measurement may in turn be used to estimate levels of minor uranium isotopes, in particular ²³⁴U, that are important for calculating the internal radiation dose received by an individual exposed to uranium. The estimation of minor isotope concentrations and the calculation of internal dose does not form part of this standard.