Studies on a specific colour reaction for the determination of testosterone

Abstract

The chromogen resulting from preliminary treatment of testosterone with concentrated sulphuric acid gives a stable green colour on further treatment with a saturated aqueous solution of picric acid. The absorbance graph of the green colour shows two maxima, at 470 and 640 nm, and obeys Beer's law. Under the specified conditions, absorbances at the two maxima have a fairly constant ratio (2·80 to 2·96), which is characteristic for testosterone and its esters in amounts ranging from 125 to 250 µg. Spectral and structural studies involving a large number of steroids show that the colour reaction is specific for testosterone.