An Ultramicro Protein-Bound Iodine Method on Capillary Blood

Abstract

A dry ash ultramicro PBI assay is described using only 10 [mu]l of serum easily obtained from a simple skin puncture. Experiments were performed to determine the loss of iodine at the various stages in the assay with the aid of I131 -labeled triiodothyronine and thyroxine. The relative value of potassium carbonate and sodium carbonate as the ashing agent was determined. The precision of the method does not differ significantly from that of the macro procedure. The nature of the brucine ceric complex was investigated. Optimum concentrations of the reactants, arsenious and ceric ions were determined to ensure greatest precision.