Formation of imine derivatives between tris(hydroxymethyl)-aminomethane and saturated 3-oxo steroids during conventional work up of biological samples dissolved in Tris-HCl buffers.

Extraction with organic solvents of Tris-HCl buffer solutions containing microgram amounts of saturated 3-oxo-steroids, followed by evaporation of the organic solvent, produce a condensation product identified as the Tris-3-imino-derivative of the steroid. The yields range between 20-40%. The conditions governing the formation of the derivatives have been explored.