URINE 539 



acetoacetic acid present in the urine will become transformed into acetone, but also 

 because of the rapid spontaneous decomposition of the alkaline hypoiodite solution 

 used in the. determination of the acetone. It has been claimed that alkaline hypo- 

 iodite solutions are almost completely converted into iodate solutions in one-half 

 hour. Folin states, however, that the transformation is not so rapid as this, but 

 he nevertheless emphasizes the necessity of rapidity of manipulation. At the same 

 time it should be remembered that the air current must not be as rapid as for am- 

 monia, inasmuch as the alkaline hypoiodite solution will not absorb all the acetone 

 under those conditions. 



Interpretation. Usually about one-fourth of the total acetone and 

 acetoacetic acid excretion is in the form of acetone, but the proportion 

 varies considerably. See Acetone and Acetoacetic Acid. 



Acetoacetic Acid 



1. Folin-Hart Method. Arrange the apparatus as described under the 

 Folin-Hart method for the determination of acetone and acetoacetic acid (see 

 page 533). Start the air current in the usual way and permit it to run 25 minutes 

 without the application of heat to the urine under examination. Under these 

 conditions the preformed acetone present hi the solution is all removed (see 

 page 538). Immediately attach a freshly prepared absorption bottle or intro- 

 duce fresh alkaline hypoiodite solution into the original bottle. Apply heat to 

 the large test-tube as already described (see page 533), in order to convert the 

 acetoacetic acid into acetone, permit the air current to continue for the usual 

 25-minute period, and determine the acetoacetic acid value in terms of acetone 

 by the usual titration procedure (see page 536). 



Interpretation. Ordinarily about three-fourths of the total acetone 

 and acetoacetic acid excretion occurs in the form of acetoacetic acid, 

 which, however, is readily transformed into acetone with loss of carbon 

 dioxide. See Acetone and Acetoacetic Acid. 



2. Folin-Messinger-Huppert and Folin-Scott-Wilson Method. Determine 

 the combined acetone and acetoacetic acid, in terms of acetone, by the Messinger- 

 Huppert method or the Scott-Wilson method (see pages 535 and 536), and sub- 

 sequently determine the acetone by Folin's method (see page 538). Subtract 

 the value determined by the second method from that obtained in either of the 

 first two methods to secure data regarding the acetoacetic acid content of the 

 urine, in terms of acetone. 



Acetone, Acetoacetic Acid, and 0-Hydroxybutyric Acid 



i . Method of Shaffer and Marriott. 1 Principle. By this procedure 

 the combined acetone and acetoacetic acid is determined in the same 

 sample of urine used in the determination of 0-hydroxybutyric acid. 

 The preformed acetone and the acetoacetic acid are distilled off to- 



1 Shaffer and Marriott: Jour. BioL Chem., 16, 265, 1915. 



