A STUDY OF THE COLORIMETRIC ASSAY OF URINARY 17-KETOSTEROIDS11

Publisher Website
Google Scholar
Abstract
In agreement with the work of Talbot, when the Callow method was employed for the detn. of 17-ketosteroids in crude extracts of urine, the use of an equation for the correction of the colorimeter readings gave results which agreed closely with those obtained by assay of the ketonic fractions separated from the crude extracts. The validity of the color correction equation was more firmly established by recovery expts. in which crystalline dehydro-iso-androsterone was added to crude extracts and to nonketonic fractions. Therefore, reasonably accurate results might be expected for the assay of crude extracts when the correction equation is used with the Callow abs. alc. method. The equation could not be applied to the readings obtained with the Holtorff-Koch method since the color given by the crude extract deviated significantly from Beer''s law. A simple blank also did not furnish adequate correction for impurities in the crude extract. However, when either method was applied to the ketonic fraction, Beer''s law was followed and both methods gave identical results. For these reasons, therefore, if accurate results are to be obtained with the Holtorff-Koch method the detn. should be made on the ketonic fraction and not on the crude extract.