The Estimation of Iodine in Foodstuffs and Body Fluids

THE study of iodine metabolism has been retarded by the technical difficulty of estimating accurately the small amounts of iodine which occur in foodstuffs and in tissues and body fluids. Kendall's method [1914, 1920], which is that most widely used at the present time, is admirably suited for the analysis of thyroid tissue, which contains roughly from 0-01 g. % to 0 5 g. % of iodine, and, as modified by Kelly and Husband [1924], it is in routine use at this Institute for that purpose. The method has, however, a lower limit of detectable iodine of 5y (y = 0-000001 g.). For the estimation of iodine in human blood, therefore, Kendall required 100 cc., since the content is only 13 y %. The method is