人工海水中における放射性亜鉛の陽イオン交換樹脂およびモンモリロナイトへの吸着挙動に及ぼす溶存アミノ酸の影響を調べた。 放射性亜鉛の吸着は亜鉛 (II) -アミノ酸錯体の安定度定数の大きさの順序に従って減少する傾向にある。しかし, アラニンが存在する場合には放射性亜鉛のモンモリロナイトへの吸着性は逆に増大した。この理由はZn2+イオンとアラニンとの配位結合に関与しないメチル基がモンモリロナイトの表面に存在する水酸基との間に相互作用をおこすためであろうと考えられる。
Model experiments for a simple and effective trapping device of volatile iodine that is generated during radioiodination of biomacromolecules were performed using an activated carbon fiber filler. Over 99.9% of the radioactivity was trappe4 by the first sheet, when a stream of the volatile radioactive iodine was passed through the layer consisting of several sheets of carbon fiber filter of pore-size 2nm preceded by two or three sheets of urethane foam filter to eliminate the water vapor, Since the carbon fiber filter has very little resistance to the gas flow, the device seems applicable to the small filter chamber for the radioiodination hood.
Liquid (toluene and dioxane) scintillation cocktail containing (methyl-3H) thymidine as a radioactive material was distilled by a rotary evaporator after storage for 0 to 12 months. The solvent obtained by distillation was then purified by several treatments, and the3H-concentration in the solvent after each treatment was determined accurately. The3H-concentration in the rotary evaporatordistillate of the cocktails reached about 0.2% of that of the original scintillation cocktails when they were stored for 12 months. But these radioactive materials could be removed completely from each solvent by several refining treatments: washing with water followed by dehydration with molecular sieves in case of toluene scintillation cocktail, and desiccation by adding excess amount of KOH in case of dioxane scintillation cocktail. It was concluded that the distillation followed by several simple refining treatments was useful to regenerate the refined solvent available for the preparation of liquid scintillation cocktail and also as a preliminary step to dispose of the waste scintillation cocktail.