A SPECTROPHOTOMETRIC STUDY OF THE OESTING COLORIMETER AND OF THE COLORS DEVELOPED WITH CRYSTALLINE ANDROSTERONE AND URINARY KETOSTEROIDS BY THE OESTING MODIFICATION OF THE ZIMMERMANN REACTION12

Publisher Website
Google Scholar
Abstract
The Oesting modification of the Zimmermann reaction was applied to the assay of crystalline androsterone and dehydroisoandrosterone in the Oesting colorimeter. The method was found relatively insensitive in that significant changes in the amt. of crystalline hormone did not appreciably affect the depth of orange-pink color which developed in the reaction mixture; and precise color matches could not be obtained between the 2 halves of the divided field in the colorimeter eyepiece even when a specific attempt was made to obtain such a match. Spectrophotometric studies were then made of the optical system of the Oesting colorimeter and compared with similar observations on the colors developed with crystalline and urinary androgens by Oesting''s method. Certain discrepancies between the two were discovered, and in order to ascertain whether they could be detected by the eye of a normal observer, the spectrophotometric data were combined with other pertinent data according to established procedures standardized by the International Commission on Illumination (1931). The results of these computations, plotted on the I. C. I. chromaticity diagram, constitute objective evidence of the inaccuracy of the Oesting method of androgen assay.