Abstract
Ammonia is determined by distillation in vacuo. 100 c.c. of blood are treated with 50 c.c. of saturated sodium chlorid solution and 250 c.c. of methyl alcohol are added to the mixture. The precipitate formed is finely granular. The residue is filtered off in a filter press, and the filtrate distilled for 40 minutes, with the temperature of the water bath at 40-50°C. The receivers are charged with n/50 sulphuric acid, and the acid titrated with n/50 sodium hydroxid free from carbonate. Sodium alizarin sulfonate is used as an indicator. The results are perfectly accurate.
The residue after distillation is made acid with hydrochloric acid, evaporated and hydrolyzed with 10 grams of glacial phosphoric acid at 150°C. The ammonia formed from the urea is then distilled into n/50 acid. The duplicates have shown very satisfactory agreement, but it is quite certain that not all the urea which is added to a sample of blood is recovered. It is probable that the carbohydrates in the residue combine with the urea at the temperature of hydrolysis and prevent the formation of ammonia.
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