ON THE QUANTITATIVE SPECTROPHOTOMETRIC DETERMINATION OF DEHYDROANDROSTERONE IN PURE SOLUTIONS

Abstract

A method for determining dehydroandrosterone in the urine is descr. The urine was treated with H2SO4 according to Dirscherl and Zilliken (Naturwiss. 31: 349. 1943). The acid gives a yellow soln. with dehydroandrosterone. The spectral composition of the reaction color was measured with a Beckman spectrophotometer, model DU. The absolute absorption max. was found at 600 m[mu]. By varying the heating time, the max. color intensity was found after 90 sec. This is considered important for reproducing the reaction. By varying the acid concn., it was found that a 50% H2SO4 soln. gave the most intense color. Where the stability of the color reaction was concerned, a 40% soln. gave a stable color almost at once, whereas the 50% concn. produced a stable reaction color only after 40 min. With both concns. the color reaction was found stable for 4 hrs. By including a dehydroandrosterone standard of 0.200 mg. with each detn., the error should amount to no more than 5%. The absorption spectra of androsterone, isoandrosterone, androstenedione and androstenediol were compared with that of dehydroandrosterone. Androstenedione gave a similar reaction but was distinguishable from dehydroandrosterone by its instability when heated for a few min. Isoandrosterone had its max. absorption at about 500 m[mu]. The sig-nificance of the method is discussed because dehydroandrosterone and isoandrosterone are both beta-ketosteroids and, hence, not separable by the digitonin precipitation.