Distillation of Used Liquid Scintillation Cocktail and the Possibility of Re-utilization of the Recovered Solvent

Abstract

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 the ³H-concentration in the solvent after each treatment was determined accurately.
The ³H-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.