Test For Presence Of Urea In Urine

Aim

To perform a test detecting the presence of urea in the given sample of urine.

Theory

What is Urine? Describe human urine.

Urine is produced by the kidney. It is a liquid waste that needs to be eliminated from the body. The kidneys eliminate the wastes from the bloodstream.

In humans, urine is a yellowish liquid containing water and several other chemical components such as uric acid, urea, traces of enzymes, hormones, and carbohydrates.

Production of Urea

It is produced naturally by the body while the proteins are disintegrated during which amino groups are eliminated from the amino acids that are in the proteins. The eliminated amino groups are converted into extremely toxic ammonia and furthermore into urea by the liver. This urea moves to the kidneys where it is finally eliminated from the body.

Detecting urea

For detection of urea in the urine sample, urease tests are performed. Urease is an enzyme that carries out the decomposition of urea into carbon dioxide and ammonia. Addition of an alkaline substance such as ammonium carbonate causes it to turn into an alkaline solution from slightly acidic urine.

1. Sodium Hypobromite Test

Material Required

  • Test tube
  • Urine sample
  • Dropper
  • Measuring cylinder
  • Sodium hypobromite solution

Procedure

  • With the help of a measuring cylinder, add 2ml urine sample from the sample bottle
  • Add the measured urine sample in the tube
  • To the sample add drops of sodium hypobromite solution using a dropper
  • Observe the changes

Observation And Conclusion

The presence of urea in the given sample of urine is indicated by a brisk effervescence around the tube of nitrogen.

2. Urease Test

Material Required

  • Urine sample
  • 1% acetic acid
  • 2% Na2CO3
  • Phenol red indicator
  • Dropper
  • Spatula
  • Measuring cylinder
  • Urease powder

Procedure

  • With the help of a measuring cylinder, add 5ml urine sample from the sample bottle
  • Add the measured urine sample in the tube
  • To the sample add 4 to 5 drops of the phenol red indicator using a dropper to the tube
  • With the help of another dropper, add drops of 2% Na2CO3 solution dropwise until the color pink starts to develop in the tube
  • Add drops of 1% acetic acid from a new dropper. Add dropwise until the color pink disappears
  • From a watch glass, with the help of a spatula, add little urease powder.
  • After addition of the powder, shake the tube well.

Observation And Conclusion

The existence of urea in the given sample of urine is indicated when a red or pink color appears in the solution.

 

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