[Trapping of volatile iodine by an activated carbon fiber filter]

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 filter. Over 99.9% of the radioactivity was trapped 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.