Urea, estimation hypobromite

Method, There are two standard methods for the estimation of urea, (i) the hypobromite method, (ii) the urease method (p. 519). The chief merit of the hypobromite method is the rapidity of the analysis the results obtained are considered sufficiently accurate for most medical requirements, e.g., for the estimation of urea in urine. For accurate metabolic work, however, the urease method should be employed. 

The hypobromite method for the quantitative estimation of the amount of urea in urine was developed about 1870. Alkaline hypobromite released nitrogen from urea, which was measured volumetrically ... 

G. Meillere, and A. Job and J. Clarens prepared a soln. of hypobromite, suitable for estimating urea in urine, by mixing eau de Javelle with an aq. soln. of potassium bromide and A. Fouchet mixed a soln. of 42 grms. of sodium bromide, and 8 5 grms. of sodium chlorate made to 100 c.c. with water, with a soln. of 50 c.c. of hydrochloric acid and 50 c.c. of water he then heated 30 c.c. of the first solution... 

This hypobromite method has largely been replaced by the more accurate and specific urease process. Urease will rapidly hydrolyse urea into ammonium carbonate and fairly stable preparations of the enzyme are available in the form of tablets. The method for the estimation of urea in urine due to Dunning is applicable using these tablets ... 

Deamination by Hypobromite.—This reaction imderlies the gasometric method of estimating urea. The condition necessary for attack is brought about by the addition of an alkali, which unmasks the amide groups. Subsequent addition of hypobromite leads to bromination of the amide groups, followed by simultaneous hydrolysis and oxidation. 

Decomposition by Hypobromite,—By measuring the nitrogen evolved as gas when urea is decomposed by hypobromite in presence of alkali, which fixes the carbon dioxide, a value is obtained which is sufficiently accurate for clinical estimations. Many different types of apparatus are in use the one now described can be improvised from a couple of 10 ml. pipettes, and is easy to assemble. 

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