74 METHODS FOR THE ANALYSIS OF URINE 



To express the result in percentage of 80s simply divide the 

 value of x, as just determined, by the quantity of urine used. 



INORGANIC SULPHATES 1 



Folin's Method 



Procedure. Place 25 c.c. of urine and 100 c.c. of water in a 200 

 to 250 c.c. Erlenmeyer flask and acidify the diluted urine with 10 c.c. 

 of dilute hydrochloric acid (1 volume of concentrated HC1 to 4 

 volumes of water). In case the urine is dilute 50 c.c. may be used 

 instead of 25 c.c. and the volume of water reduced proportion- 

 ately. Add 10 c.c. of 5 per cent barium chloride slowly, drop by 

 drop, to the cold solution and from this point proceed as indicated in 

 the method for the determination of Total Sulphates, page 73. 



Calculate the quantity of inorganic sulphates, expressed as 80s, 

 in the twenty-four-hour urine specimen. 



Calculation. Calculate according to the directions given 

 under Total Sulphates, page 73, 



ETHEREAL SULPHATES 2 



Folin's Method 



Principle. The inorganic sulphates are removed with barium 

 chloride and the conjugated sulphates then determined after 

 hydrolysis. 



Procedure. Place 125 c.c. of urine in an Erlenmeyer flask of 

 suitable size, dilute it with 75 c.c. of water and acidify the mixture 

 with 30 c.c. of dilute hydrochloric acid (1 volume of concentrated 

 HC1 to 4 volumes of water). To the cold solution add 20 c.c. of 

 a 5 per cent solution of barium chloride, drop by drop. Allow the 

 mixture to stand about one hour, then filter it through a dry filter 

 paper. Collect 125 c.c. of the filtrate and boil it gently for at 

 least one-half hour. Cool the solution, filter off the precipitate of 

 BaSC>4, wash, dry and ignite it according to the directions given 

 on page 73. 



1 Folin: Jour. Biol. Chem., 1905, 1, 131. 



2 Ibid. 



