Cambridge O Level Biology · Syllabus 5090 · Biological Molecules
Biuret Test
What is Biuret Test?
A food test for protein. Biuret reagent as supplied by the centre is added to the sample, or sodium hydroxide solution is added first and then a small amount of dilute copper(II) sulfate solution, following the centre's approved method. A blue mixture turns lilac or purple when protein is present, and stays blue when protein is not detected. No heating is required.
This definition is part of the Biological Molecules chapter in Cambridge O Level Biology.
Last reviewed Syllabus 2026-2028