계란중 요드의 간편한 비색 측정법

A modified specrophotometric method for the determination of iodine in eggs

A simple and relatively accurate method to determine iodine in iodine-enriched eggs was developed by modifying spectrophotometry and summerized as following: Egg yolk and egg white were digested by ethanol and potassium hydroxide on the steam bath, and free and protein-bound iodine were converted to potassium iodide by these procedures. The samples were dried, charred and then ashfied at 500℃ for 4 hours. Potassium idodide in ash residue was extracted and washed with distilled water. The potassium iodide in extract was treated with 6N sulfuric acid and 3% hydrogen peroxide solution to liberate free iodine. The free iodine was extracted with chloroform and the absorbance of iodine in chloroform was determined at the wave length of 510nm with chloroform blank. Although carbon tetrachloride and carton disulfide were found being better solvents for iodine in intensity of absorbance and in efficiency of extracting iodine, the authors recommend chloroform as an iodine solvent, since chloroform was less toxic and more benefit to handle and the iodine content in iodine-enriched eggs is high enough to determine with chloroform. The iodine contents in normal eggs, iodine-enriched eggs in Korea and in Japan and in the sea weeds were reported. Distribution of iodine in egg albumin and egg yolk was also described. The authors recommend this method as an assay method of iodine in livestock products.