764 URINE. 



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 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 (b) a solution containing 6.55 grams hydrox- 

 ylamine sulphate in 2 liters. 



The copper solution is prepared in the following manner : 500 grams potassium 

 carbonate, 400 grams potassium thiocyanate and 100 grams potassium bicar- 

 bonate are dissolved in 1200 cc. water in a graduated flask and if necessary 

 warmed to 50-60 C. On cooling to the ordinary temperature add very slowly 

 150 cc. of a cool, aqueous solution of cupric sulphate which contains 25 grams 

 cupric sulphate (CuSO 4 -h5H 2 0) in 150 cc.; then add water up to 2 liters. After 

 standing at least 24 hours filter, and this solution can be kept indefinitely. The 

 hydroxylamine solution is prepared by dissolving 200 grams potassium thiocyan- 

 ate 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 also 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 cop- 

 per 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. If more than 3 per cent sugar is 

 suspected in the urine the latter must be diluted with a known amount of 

 water. In the estimation 10 cc. of the fluid containing sugar is always 

 used. If the urine contains less than 0.6 per cent sugar, then 10 cc. are 

 used; otherwise, according to the amount of sugar, 5-2 cc. of the urine 

 are diluted with water to 10 cc. and this used in the determination. 



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

 in a g]ass 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- 

 ylamine solution allowed to flow in from a burette until the blue color 

 disappears and the solution is colorless, or, in urine poor in sugar, is yellow. 

 This yellow coloration may disturb the end reaction somewhat, so that 

 with inexperienced workers an error of 0.5 cc. hydroxylamine solution 

 (corresponding to 0.5 milligram sugar) may be the result. If necessary 

 the urine can be decolorized, according to ANDERSEN, by mercuric nitrate. 



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



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

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



3 Bioch. Zeitschr., 2 and 11. See also Funk, Zeitschr. f. physiol. chem., 56; Jessen- 

 Hansen, Bioch. Zeitschr., 10 and Andersen, ibid., 15. 



