URINE 561 



contains the phenols from one-half the amount of urine analyzed. The actual 

 determination of phenols, both free and total, is made upon a two-fifths portion 

 of this filtrate and this amount of filtrate contains the phenols from one-fifth 

 of the amount of urine analyzed. In the determination of free phenols the colored 

 solution is diluted to only half that of the standard while in the determination 

 of total phenols the dilution is the same as that of the standard. 

 Hence, 



n 



n ^ = milligrams of free phenol 



K.2 X 4 



and 



T> 



p * = milligrams of total phenol 



K.2 X 2 



in 2 c.c. or 4 c.c. of urine according to whether 10 c.c. or 20 c.c. of urine was 

 taken for analysis, when Ri is taken as the reading obtained with the standard 

 solution, and R 2 is taken as the reading obtained with the unknown. 



Interpretation. This method determines all phenolic substances 

 e.g., the volatile phenols p-cresol and phenol, the non- volatile phenol 

 pyrocatechol and the aromatic oxyacids p-oxyphenylacetic acid, p- 

 oxyphenylpropionic acid and p-oxybenzoic acid. All these substances 

 are formed from tyrosine. By this method total phenol excretions of 

 from 0.2-0.5 gram per day have been noted in normal individuals. 

 These results are much higher than figures previously obtained by other 

 methods. The free phenols varied from 0.1-0.3 gram per day. The 

 total phenol excretion appears to vary directly but not proportionately 

 with the protein intake. The amount of conjugated phenol indicates 

 the extent to which the phenols have been detoxicated. The excretion 

 of phenols is increased in gastro-intestinal disorders associated with 

 increased putrefaction. It is increased by the ingestion of phenols or 

 of benzene. Constipation influences the phenol output to a greater 

 extent than diet. 1 Diets which promote the growth of putrefactive 

 bacteria also promote indican and phenol excretion. A high phenol 

 output does not necessarily mean a high indican excretion. 



TisdalPs Modification of Folin-Denis Method. 2 Principle. The 

 phenolic substances are extracted from the urine with ether, the ether 

 solution extracted with 10 per cent NaOH, and the phenols determined 

 colorimetrically as in Folin-Denis method p. 559. 



Procedure for Free Volatile Phenols. Five c.c. of urine are shaken for five 

 minutes with 100 c.c. of ether. The urine is separated and two more extrac- 

 tions are made, using 50 c.c. of ether each time. The 200 c.c. of ether are 

 shaken for 5 minutes with 20 c.c. of 10 per cent NaOH, separated, and the 

 sodium hydroxide solution is neutralized and made slightly acid with concen- 

 trated HC1. Sodium carbonate and the phenol reagent are then added as in the 

 Folin-Denis method p. 559. 



1 Underbill and Simpson: Jour. Biol. Chem., 44, 69, 1920. 

 2 Tisdall: Jour. Biol. Chem., 44, 409, 1920. 

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