Test for Organic Constituents: (any 3)

 

Test for Organic Constituents: (any 3)

 

a) Urea:

               

                Urea is formed in liver as the end product of protein metabolism and so its excretion depends on protein intake.

 

                About 20-30 gm urea is excreted in 24 hours.

 

i) Sodium Hypobromite Test

 

                To 2ml of urine add a few drops of *freshly* prepared sodium hypobromite solution

A brisk effervescence due to the evolution of gaseous nitrogen is observed.

 

ii) Urease Test:   

 

                This test depends on the fact that the enzyme urease hydrolyses urea into ammonia which makes the solution alkaline.

 

                To 2ml of urine add few drops of phenolphthalein indicator and a few drops of a freshly prepared Urease solution. Wait for 15 minutes, solution becomes pink due to the formation of ammonia, indicating the presence of urea.

 

b) Uric Acid

                Uric acid is the end product of purine metobolism. The daily output of uric acid varies in the range of 0.6 to 1 gm.

 

                Alkalies dissolve uric acid in the form of urates. It is insoluble in water. In gout the uric acid level in bi blood increased. Uric acid is greatly excreted in urine in conditions like leukemia, polycythemia – uric acid output decrease in renal failure.

 

Folin and Dennis Test:

                To 2ml of urine add 1ml 10% sodium carbonate and 1ml of phosphotungstic acid. Development of blue colour indicates the presence of uric acid.

 

c) Ethereal Sulphates

                Ethereal sulphates in urine are the conjugated phenols, like phenol sulphuric acid and indican. These ethereal sulphates result from phenols produced during purification of protein material in the intestine. This is conjugated in the liver to form ethereal sulphates. About 100 mg of ethereal sulphates are excreted per day.