Abstract
The concentration, isotopic composition, and alpha activity of uranium in urine are determined in one analysis by isotopic dilution and surface ionization mass spectrometry. The isotope 233U is added as an internal standard, and the uraniumi is extracted with tri-n-octylphosphine oxide for the mass spectral analysis. The complete analysis is obtained on as little as 0.1 μg of uranium. The relative standard deviations are ±1% to ±8% at 10 μg of uranium per liter of urine.