Methods for the Quantitative Estimation of Nanogram and Subnanogram Amounts of Steroids in Blood and Urine

I. INTRODUCTION

The determination of metabolites in human body fluids requires the development of analytical methods capable of providing both quantitative and qualitative information for a relatively large number of compounds, notably steroids, in complex mixtures. Prior to 1955, work on the isolation and identification of steroids had employed solvent partition, adsorption chromatography, digitonin precipitation, the use of Girard reagents, and a number of other techniques more common in organic chemistry. Despite the obvious progress that these techniques had made possible in the steroid field, it was apparent that other concepts would be needed in order to develop specific and quantitative methods for the determination of steroids in biological samples and especially for the determination of the relatively low concentrations of steroid hormones in blood and urine.