Automation of Protein-Bound Iodine Determinations

Portions of the Barker alkali-incineration technic for determining protein-bound iodine have been automated usingan automatic analysissystem. The manifold and analytic procedureare describedin detail. Data are presentedto showthat the auto-mated procedurecomparesfavorablyin accuracywith the manualprocedure. RECENT YEARS have seen increased clinical use of serum protein-bound iodine values as an aid in assessing thyroid function. Conse-quently, this and numerous other clinical laboratories have been over-burdened with requests for performance of a determination sufficient-ly complex as to require the devoted attention of a skilled analyst. In order to conserve the time involved for such valuable technical person-nel, it was decided to automate certain portions of the Barker alkali-incineration technic (1,2). Reagents and Materials The reagents listed below are prepared according to directions giv-en by Barker et al. (1), with slight modifications that are described. iDemineralized water, containing less than 1 ppm impurities, is used in preparing all solutions. Zinc sulfate, 10 % w/v