ESTIMATION OF SUGAR IN URINE. 809 



Of the titration methods with copper solutions the method suggested 

 by BANG is the simplest, and at the same time seems to be more reliable 

 than any of the others. For this reason we will describe only this method 

 and refer to the original works and to HOPPE-SEYLER-THIERFELDER, 

 Handbuch der Chem. Analyses, 1909, for description of the titration of 

 FEHLING'S solution according to SOXHLET l and to the titration accord- 

 ing to PAVY and KuMAGAWA-SuTO. 2 



BANG'S First Method. 3 The principle of this method is that when urine 

 is boiled with an excess of a solution of potassium carbonate, potassium 

 thiocyanate and copper sulphate, copper thiocyanide is formed, and this 

 remains in solution as a colorless compound. The excess of cupric 

 oxide remaining is determined by titration with a solution of hydroxyl- 

 amine until the blue color disappears. The quantity of sugar is calculated 

 from the quantity of hydroxylamine used. 



The following solutions are necessary: (a) A copper salt solution 

 containing 25 grams cupric sulphate in 2 liters, and (6) a solution con- 

 taining 6.55 grams hydroxylamine sulphate in 2 liters. 



The copper solution is prepared in the following manner: Dissolve 100 grams 

 potassium bicarbonate in 1300 cc. water in a 2-liter graduated flask, and if nec- 

 essary warm to 50-60 C. After complete solution of the bicarbonate, add 

 400 grams potassium thiocyanate and 500 grams potassium carbonate. To 

 this solution, which must have the temperature of the room, add very slowly 

 150 cc. of a copper sulphate solution, which contains 166.67 grams copper sul- 

 phate (CuS0 4 +5HiiO) per liter, then add water up to 2 liters. This solution 

 unfortunately does not keep indefinitely, still, according to ANDERSEN, it can be 

 kept in the dark up to 3 months and its strength controlled by titration with the 

 hydroxylamine solution. The hydroxylamine solution is prepared by dissolving 

 200 grams potassium thiocyanate in about 1500 cc. water in a 2-liter graduated 

 flask and adding a solution of 6.55 grams hydroxylamine sulphate in water; then 

 add water to the 2-liter mark. This solution, on the contrary keeps, but it must 

 be kept in a dark-colored bottle. Equal volumes of each of these two solutions 

 should exactly correspond to each other, and this can be determined by titrating 

 at ordinary temperature 50 cc. of the copper solution (plus 10 cc. water) with the 

 hydroxylamine solution. 



The presence of proteid does not interfere with the reaction, and it 

 is not necessary to remove the proteid. The urine for titration should 

 not contain more than 0.6 per cent sugar. If the amount is lower, then 

 10 cc. of urine is used directly; if it is higher, then the urine is corre- 

 spondingly diluted and of this diluted urine we also make use of 10 cc. 

 in the titration. The quantities of sugar given in the table below vary 

 between 0.9 and 60 milligrams in 10 cc. 



Performance of the Determination. 10 cc. of the sugar fluid are placed 

 in a glass flask and treated with 50 cc. of the copper solution. This is 

 heated on a wire-gauze to boiling, boiled for three minutes, cooled 

 quickly with water to the temperature of the room and then the hydrox- 



1 Journ. f. prakt. Chem., (N. F.), 21. 



2 Pavy, The Physiology of the Carbohydrates, London, 1894; Kumagawa and Suto, 

 Salk'owski's Festschr., 1904; Sahli, Deutsch. med. Wochenschr., 1905. 



3 Bang, Bioch. Zeitschr., 2, 11, 32, and 38. See also Funk, Zeitschr. f. physiol. 

 Chem., 56 and 69; Jessen-Hansen, Bioch. Zeitschr., 10 and Andersen, ibid., 15 and 26. 



