Gas Chromatographic Procedures for the Measurement of Pregnanediol, Andosterone, Etiocholanolone, and Dehydroepiandrosterone

A search for urinary steroids that conform with the conditions has led to the development of assays for etiocholanolone, dehydroepiandrosterone, pregnanediol, and for etiocholanolone and androsterone together. In each case the preparation of 40 samples for gas chromatography takes less than 4 hr, and each chromatographic analysis between 10 and 20 min. Pregnanediol occurs in urine mainly as the glucuronide. Before the advent of gas chromatography, urinary pregnanediol was assayed both gravimetrically and colorimetrically. There have been many reports of the instability of pregnanediol in the presence of hydrochloric acid. The effect has been confirmed and the rate of pregnanediol decomposition measured as a function of acid strength. Many workers use free pregnanediol as standard for their pregnanediol assays, but few treat urine samples and standard solutions in a comparable manner. Gas chromatograms of method blanks resemble those seen in the pregnanediol assay and are not dissimilar to the tracings obtained when urine from dexamethasone-suppressed patients is analyzed.