Methods for the Determination of lodine-131 in Fresh Milk

The investigation was carried out in order to find an improved method to determine iodine-131 in fresh milk. (1) In order to minimize iodine loss during ignition of milk, it was recommended to add an NaOH solution to the milk in ratio of milk to the 1 N NaOH solution as 1: 19. (2) A series of experiments indicates that inorganic iodine combines with fat and protein during experimental operation by Bergh's method. Since the iodine in fat-CCl4 layer is not determined, Bergh's method is thought to be unreliable. (3) To determine inorganic iodine, a composite system of ion-exchange and CCl4 extraction was recomended in the paper. If the assumption, about 90 percent of iodine in milk exists as inorganic form, is accepted, total iodine-131 concentration could be easily calculated from the measurement of the above.