Determination of iodoamino acids and inorganic iodide by thin-layer chromatography.

Many methods for the determination of iodinated compounds in thyroid extracts by paper and thin-layer chromatography have been reported. Some of them do not separate inorganic iodide (l-3)) diiodothyronine (4-8)) or monoand di-iodotyrosines (6, 9). Others use more than one solvent system (4, 7, lO-12), usually one system for iodotyrosines and another for iodothyronines. Still other show poor separation of the compounds (2, 7)) or are not supported by adequate recovery data (l-3, 5-9, 11, 12). However, good separation (3, 5, 10, 11) and recovery (4, 10) have been achieved in several laboratories. In our study of the synthesis of iodinated compounds in thyroid tumors, we have developed a solvent system for the separation and quantitative determination of thyroidal iodine-containing compounds including inorganic iodide by thin-layer chromatography. This paper describes our method and its application to 1311 experiments in z&o.