Abstract
A practical method for separation and quantitative estimation of human thyroid hormones by thin layer chromatography (TLC) is presented. Thin layer chromatography was performed in Kieselguhr G plate washed with 10% HCl. This HCl washing was effective in removing the substances which interfered with the measurement of the iodo amino acid by eerie sulfate-arsenious acid reac- tion. The elution rates of iodo amino acids from thin layer chromatogram were 92% for 3-monoiodo-l-tyrosine (MIT), 93% for 3, 5-diiodo-l-tyrosine (DIT), 90% for 3, 5, 3'-triiodo-l-thyronine (T3) and 92% for l-thyroxine (T4) respectively. The correlation between the quantity of thyroid hormones and optical density was proved to be linear. The extraction rates of each iodo amino acid from human plasma were 75% for MIT, 62% for DIT, 73% for T3 and 63% for T4, and the factors of 1.33 for MIT, 1.61 for DIT, 1.37 for T3 and 1.59 for T4 were calculated. It might be possible to determine the quantity of circulating thyroid hormones by multiplying these factors by the estimated values from the eerie sulfate-arsenious acid color reaction.
