Gas chromatographic determination of free and solvalysable dehydroepiandrosterone and androsterone in blood

An improved gas chromatographic method is reported for the determination of unconjugated and solvolysable dehydroepiandrosterone and androsterone in plasma. Free steroids below a level of 1 μg/100 cm3 are determined as heptafluorobutyrates by electron capture detection following extraction and thin-layer chromatographic purification. Free steroids above 1 μg/100 cm3 and steroid sulphates are measured as acetates using flame ionisation detection following solvolysis, extraction and thin-layer chromatography. Control experiments and representative normal values prove that the method is suitable for the determination of steroids in human, rat and dog plasma.