Application of atomic absorption spectrometry for the quantitative determination of metallic impurities in pure uranium compounds.

Several elements (V, Mo, Fe, Mn, Cd, Zn) as metallic impurities in pure uranium compounds were quantitatively determined by atomic absorption spectrometry. The effects of uranium and that of other factors on the absorption intensity of each element were studied. The analyzed samples were dissolved in 6 M nitric acid, and uranium was selectively extracted with tributylphosphate. The aqueous solution containing impurities was then evaporated and the obtained moist residues were dissolved in dilute hydrochloride acid or nitric acid. The sample solution was measured with a flame atomic absorption spectrometer under the optimum conditions, such as the maximum wavelength, suitable ratio of acetylene-air or acetylene-nitrogen oxide mixture, and some other parameters of the instrument. The analytical procedure was applied in laboratories belonging to Vietnam Atomic Energy Commission for the determination of these above-mentioned elements in synthesized uranium samples and in purified uranium oxide samples with high precision and accuracy.