Gas Chromatographic Analysis with Electron Capture Detection of Thyroid Hormones

Abstract

A gas chromatographic system is described for the separation and detection of the thyroid hormones at the very low levels of these substances found circulating in the blood. It has been shown that the derivatives employed, the N,O-dipivalyl methyl esters, are particularly well suited to this analysis. These derivatives have the advantages of ease of preparation, resistance to hydrolysis by moisture, and especially thermal stability. Chromatographic separations have been carried out using 1 and 2 mm i.d. × 3 ft packed columns with polysulfone and 0V-17 as the stationary phase and a Barber-Colman Model 5360 gas chromatograph with a 0.056 mC high temperature radium detector. A linear response was obtained for these compounds in the nanogram and picogram range. The adaptation of this procedure to the analysis of serum samples is illustrated.