Biuret's test for proteins

• What equipment is needed for the Biuret test?

  Test tube, 10 cm³ measuring cylinder, Biuret solution.
• What is the first step of the Biuret test?

  Add a few drops of Biuret's reagent (sodium hydroxide and copper (II) sulphate) to the food sample in a test tube.
• What is the second step of the Biuret test?

  Shake the solution to mix and wait for a few minutes.
• What is the third step of the Biuret test?

  If protein is present, the solution turns from blue to purple.
• Mnemonic: Biuret turns purple, protein's the hurdle


  Biuret - Blue to purple - Proteins