116 LABORATORY WORK IN PHYSIOLOGICAL CHEMISTRY. 



(Folin). The urates are finally titrated with -^ potassium 



permanganate . 



Quantitative Estimation. 

 Reagents necessary: 



1. 500 grms. (NH 4 ) 2 S0 4 , 5 grms. uranium acetate, and 

 60 c.c. of 10 per cent acetic acid dissolved in water and the 

 mixture made up to a liter. 



2. KTT K 2 Mn 2 8 titrated against a ^ solution of oxalic 



acid. 



Place 300 c.c. of urine in a beaker, add 75 c.c. of the 

 ammonium sulphate reagent and mix thoroughly. After 

 the resulting precipitate has settled sufficiently (5 minutes), 

 the mixture is filtered through a double-folded filter. When 

 250 c.c. of the filtrate have passed through, this volume is 

 divided into two portions of 125 c.c. each, to serve as dupli- 

 cates. To each portion add 5 c.c. of concentrated NH 4 OH, 

 mix thoroughly, and allow them to stand for 24 hours. The 

 precipitated ammonium urate is then transferred quanti- 

 tatively to a filter, using a 10 per cent (NH 4 ) 2 SO 4 solution 

 to remove the last portions of the precipitate from the beaker. 

 After removing the filter-paper from the funnel and opening 

 it up, the precipitate is washed with about 100 c.c. of water 

 into the same beaker in which the ammonium urate was 

 precipitated; to this 15 c.c. of cone. H 2 S0 4 is added and the 



N 

 mixture immediately titrated with the ^: K 2 Mn 2 8 solution, 



which is added from a burette until the first permanent 



N 

 tinge of pink color appears. 1 c.c. of ^ K 2 Mn 2 8 solution = 



3.75 mg. uric acid. Calculated the quantity of uric acid in 

 the 24-hour sample. 



