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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, 1
(
.)()’.), 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 0.55 grams hydroxylamine sulphate in 2 liters.
The copper solution is prepared in the following manner: Dissolve 100 grams
potassium bicarbonate in 1300 ec. water in a 2-liter graduated flask, and if nec-
essary warm to 50-60° C. After complete solution of the bicarbonate, add
400 grains 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 (CuS04+5H^O) 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,
Salkowski’s Festschr., 1904; Sahli, Deutsch. med. Wochenschr., 1905.
J
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.
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