Determination of tritium in human urine

The content of tritium oxide in human urine was estimated by means of liquid scintillation method. Urine sample was purified with 1:2 cation-anion mixed ion exchange column (Diaion, 100∼200 meshes, H and OH-types, φ 1 cm, h 10 cm), in order to remove both organic and inorganic salts which might bring about the quenching effect in the scintillation. The radioactivity of tritium was measured at room temperature after 1 ml portion of the deionized sample was added into 60 ml liquid scintillator. The scintillator was prepared by dissolving 4 g PPO and 15 mg POPOP in the mixed solvent of 230 ml ethanol-770 ml toluene. Although as low as 0.01 μc/ml of tritium can be estimated at room temperature with 10% error, the present method is also applicable to the determination of tritium in radioactive liquid wastes with slight modifications. (author)