The Biuret Test is often used to determine the presence of peptide bonds in protein. As a secondary school student you will be testing for the presence of protein in foods.
Instead of the Biuret Reagent, either of the following may be used:
The Biuret test for proteins may also be extended to quantitatively measure the concentration of total protein using spectrometric methods.
Observations & Interpretation
Look for colour changes in the solution. These are best visualized against a white background such as a white tile or a sheet of paper.
Did you know? The biuret reagent is not named after someone but a substance called biuret (H2NC(O)NHC(O)NH) – the result of the condensation of 2 molecules of urea. The reagent is so named because the peptide bonds in biuret give a positive result for the test.