Borodin's Method

BORODIN'S METHOD of urea determination is based on the decomposition of the latter by hypobromite liquor into water, nitrogen, and CO₂: the carbon dioxide is absorbed by the alkali, and the urea content is calculated from the volume of released nitrogen. The determination is performed

in a special apparatus of Borodin, shown in the figure. Reagents: 1) 30 g of caustic soda is dissolved in 1 l of water, and 50 g of bromine is added to the liquid after cooling; 2) saturated sodium chloride solution. - Method of execution. The apparatus is filled with solution (2) through tube B until it emerges into A above the stopcock. The stopcock is closed and the saline solution is discharged from A through the side opening of the stopcock. 5 cubic centimeters of urine, diluted 5 times with water, are lowered from A into B above the saline solution, with which the urine does not mix due to the difference in specific gravity. Then, hypobromite liquor (1) is lowered in small portions into B until the evolution of gas bubbles ceases. After 30 minutes, the volume of gas is measured. Using tables, the quantity of urea corresponding to 1 cubic centimeter of N at the existing temperature and pressure is found. The method is sufficiently accurate and is used for the quantitative determination of urea in urine. For blood, this method was modified by Saveliev.