The Colorimetric Determination of Phenols in the Blood

In 1915, Folin and Denisb described a method for the determination of free and conjugated phenols in the urine, using a phosphotungstic-phosphomolybdic reagent, which, in the presence of sodium carbonate, gives a color reaction with phenols. The formula for the color reagent was published in 1912,2 at the same time as the uric acid reagent. Later, Folin and Denis applied the method to phenols in the feces. Little has been done since in phenol determinations, except’ by Dubin, who published papers on the formation and elimination of phenols under normal and pat,hological conditions;’ and on the effect of feeding inosite on the elimination of pheno1s.j In connection with some work which we have been doing on the chemical analysis of blood in carcinomatous patients, we aftempted to apply t,he color reaction to the determination of phenols in the blood. A method has finally been worked out, which we believe to be reasonably simple and accurate. In brief, our method provides for the determination of (a) uric acid in one sample of the blood, and (b) of uric acid and phenols in a second sample of the same blood. The phenol content of the blood is then obtained by difference. At present this procedure seems preferable to one based upon any attempt to separate the uric acid from the phenol, and to determine the