Scientific Proceedings. 



105 



72 (215) 



On the separate determination of acetone and diacetic acid in 



diabetic urines. 



By OTTO FOLIN. 



[From the Chemical Laboratory of McLean Hospital, Waverley, 



Mass.] 



The Messinger-Huppert method is valuable for the determina- 

 tion of acetone and diacetic acid in urine but it gives only the sum 

 of these two products and there is manifestly need of an additional 

 quantitative method for the separate determination either of acetone 

 or of diacetic acid. 



While acetone is a liquid with a boiling point of 56°C. and dis- 

 solves in water in all proportions, I have found that it can be 

 removed from its solutions by means of an air current and at ordi- 

 nary room temperatures even more readily than ammonia. It can 

 be determined in about half an hour, according to the same prin- 

 ciple and by the help of the same apparatus which I use for the 

 determination of ammonia. The determination is made as follows : 



Measure 20—25 c.c. of acetone solution or urine into an aero- 

 meter cylinder and add 0.2-0.3 gm. oxalic acid or a few drops of 10 

 per cent, phosphoric acid, 8-10 gm. sodium chloride and a little 

 petroleum. Connect with the absorbing bottle (as in the ammonia 

 determination) in which has been placed water and 40 per cent. 

 KOH solution (about 10 c.c. of the latter to 150 c.c. of the 

 former) and an excess of a standardized solution of iodine. Con- 

 nect the whole with a Chapman pump and run the air current 

 through for 20-25 minutes. (The air current should be fairly 

 strong but not as strong as for the ammonia determination.) 

 Every trace of the acetone will now have been converted into 

 iodoform in the receiving bottle. Acidify the contents of the lat- 

 ter by the addition of concentrated hydrochloric acid (10 c.c. for 

 each 10 c.c. of the strong alkali used) and titrate the excess of 

 the iodine, as in the Messinger-Huppert method, with standard- 

 ized thiosulphate solution and starch. 



The determination of the acetone can be made simultaneously 

 with the determination of the ammonia with the use of the same 

 air current and even in the same sample of urine but I do not 



