Anion-exchange and solvent extraction studies on the separation of radioiodine with particular reference to the production of 123I via proton irradiation of 123Te metal target

The separation of radioiodine was investigated using two wet chemical procedures, namely anion-exchange and solvent extraction. Some factors affecting the separation, such as HCl, NaOH and tetrabutyl ammonium bromide (TBAB) concentrations, used solvents ethyl acetate, benzene and carbon tetrachloride and different quaternary ammonium salts were studied. For each procedure the optimum conditions were deduced. The separation of I-123 was effected from proton-irradiated Te-123 target under the optimized conditions of the two procedures. The yield of I-123 obtained using the Dowex 21k anion-exchanger and tetrabutyl ammonium bromide solution as eluting agent was 88 +/- 3%; the radionuclidic purity was high and the time needed was 60 minutes. In solvent extraction process using TBAB in ethyl acetate as the extracting agent, the yield of I-123 was low (47 +/- 3%), the radionuclidic purity was not as good as in the anion-exchange method, and the time needed was 150 minutes. Therefore, the anion-exchange method is preferable. A comparison of this wet chemical method of separation of I-123 with the commonly used dry distillation method is given. The wet method appears to be more suitable when a Te-123 metal target is used.