Abstract
The use of tetramethylammonium hydroxide (T.M.A.H.) in place of potassium hydroxide in the Zimmermann reaction has been investigated. Although various pure steroids have different colour equivalents, a comparison of the results of 17-ketosteroid and 17-hydroxycorticosteroid estimations on a series of urines showed that the differences for the two reagents were only small and may be ignored. Tetramethylammonium hydroxide has the considerable advantage over potassium hydroxide of stability and need not be prepared freshly. The correction procedures available are discussed.