Determination of molybdenum and uranium in biological materials by radiochemical neutron activation analysis

Recently developed radiochemical separation scheme for the simultaneous determination of trace amounts of molybdenum and uranium in biological materials by NAA has been further refined and used for the determination of these elements in several certified reference materials. The method assures very selective and quantitative separation of the indicator radionuclides: Mo-99-Tc-99m and Np-239 from practically all accompanying activities followed by almost interference-free measurement by gamma ray spectrometry. The method can be applied to materials of both animal and plant origin and enables correcting the molybdenum results for uranium fission interference reaction thus assuring good accuracy for both elements down to ppb levels. The detection limits amount to 2.5 ppb (Mo) and 0.15 ppb, (U) for ca. 200 mg samples.