Study on Iodine Labelling (I) Influences of Reducing Agent and Iodate- 131 I in Sodium iodide- 131 I solution on Labelling

In iodine-131 labelling of iodocompounds such as tetrachloro-P-tetraiodo R-fluorescein, sodium orthoiodohippurate and a non-iodocompound, human serum albumin (HSA), the labelling rates and yields are accurately compared with each other. The reaction systems conducted for each compounds were different conditions: sodium iodide- I containing reducing agent, sodium iodide- I free from reducing agent, and sodium iodide- I free from reducing agent but containing considerable amount of iodide- I etc. The labelling yields were generally poor; 10% in the case of using sodium iodide- I containing redoing agent, and 50~60% in the case of using sodium iodide- I free from reducing agent but containing considerable amount of iodide- I. However, fair yields were obtained in the case of using sodium iodide- I free from reducing agent and mostly in the form of iodide- I. The reaction entities involved in these reactions are also briefly discussed.