66 



METHODS FOR THE ANALYSIS OF URINE 



SPECIAL FACTORS FOR CALCULATION OF RESULTS WHEN 25 c.c. 

 OF URINE FILTRATE, EQUIVALENT TO 2.5 c.c. OF URINE, 

 ARE USED FOR THE DETERMINATION 



In order to calculate the acetone bodies as /3-hydroxybutyric 

 acid rather than acetone, use the above factors multiplied by the 



5~jipi(i 104 



ratio of the molecular weights -^- = 1.793. In order to 



acetone 58 



calculate the acetone bodies in terms of molecular concentration, 

 divide the factors in the table by 58. To calculate c.c. of 0.1 M 

 acetone bodies per liter of urine use the above factors multiplied 



ACETONE 



Folin's Method 1 



Principle. The preformed acetone is aspirated from the urine 

 mixture at room temperature to prevent decomposition of aceto- 

 acetic acid. The acetone is collected in alkaline hypoiodite 

 solution as in the Folin-Hart method. lodoform is formed quanti- 

 tatively and the excess of iodine is titrated with sodium thiosul- 

 phate. 



Procedure. The same type of apparatus is used in this 

 method as that described in Folin's method for the determination 

 of ammonia (see page 42). Introduce 20 to 25 c.c. of the urine 

 under examination into the aerometer cylinder and add 10 drops 



Jour. Biol. Chem., 1914, 18, 263. 



