The biuret test, also known as Piotrowski's test, is a chemical test used for detecting the presence of peptide bonds. In the presence of peptides, a copper(II) ion forms mauve-colored coordination complexes in an alkaline solution.
What is biuret assay method?
The biuret method is a colorimetric technique specific for proteins and peptides. Copper salts in alkaline solution form a purple complex with substances containing two or more peptide bonds. ... Thus, the biuret reaction with proteins is suitable for the determination of total protein by spectrophotometry (at 540–560 nm).
How does biuret test for protein?
Biuret test for proteins
- Place one-two spatulas of the food sample into a test tube or 1 cm 3 if the sample is liquid. ...
- Add an equal volume of potassium hydroxide solution to the tube and stir.
- Add two drops of copper sulfate solution and stir for two minutes.
- Record the colour of the solution.
