How can urea be detected by the Biuret test?

The Biuret test is typically used to detect proteins, not urea. It involves adding a reagent (usually a solution of copper sulfate and sodium hydroxide) to a sample. Proteins contain peptide bonds, which react with the copper ions in the reagent, producing a violet or purple color. This color change is a positive result for proteins.

Urea, on the other hand, does not contain peptide bonds and therefore does not produce a color change in the Biuret test. To detect urea specifically, other tests, like the urease test or the urease breath test, are used.