5, Gardyna H. Determination of total iodine in urine, stool, diets, and tissue. Clin Chem 1965;11

A method is presented for determination of total iodine in biologic material. The pro-cedure requires a minimum number of reagents, eliminating the possibilityof reagent iodine contamination. The actual cost of equipment for this method is less than for others, and the method offers goodreplication and excellent recoveryof added iodine. 13ETIiRMINATION of total iodine in various materials has become of increasing interest, especially in nutritional studies. Several methods are available for such determination. Many of them have been princi-pally concerned with the protein-bound iodine fraction in serum (1, 2). Other methods for iodine determination have appeared from time to time. Mathews et al. (3) have proposed a method which requires large amounts of biologic specimens for good results. Widstr#{246}mand Bj#{246}rk-man (4) have reported that losses of iodine by the dry-ash technic could be minimized by using potassium carbonate in place of sodium carbonate. Van Middlesworth (5) found that the Barker dry-ash method gave low recovery rates, in the range of 68-86%. Widstr#{246}mand Claeson (6) found that for the determination of total iodine in urine, a carrier me-dium such as zinc hydroxide was necessary to prevent losses of iodine with the dry-ash technic. Rodgers and Poole (7) advocated wet-ash digestion after which the iodine is distilled off by use of a special distilla-tion apparatus. Barkley and Thompson (8) have reported an ampero-metric method for determination of total iodine in sea water; this method is not applicable directly to specimens of a biological nature. Since the method of Zak, as modified by two of us, has worked well for determination of protein-bound iodine and total iodine in serum (9), we decided to investigate its reliability for the determination of total iodine in urine, stool, diet, and tissue