Biuret Test

Biuret test is chemical test to detect the presence of proteins, especially the presence of peptide bond.
Peptide bond is bonding each amino acids in the protein. Biuret can't detect the single amino acids, because there aren't peptide bond in it. Positive result will showing purple color, Cu++ will reacting with NH from peptide bond and O from water and show the purple color of solution. Long proteins show purple color, short proteins show pink color.

Important in this test is:
1. NaOH 10 %
2. CuSO4 0,1%

Procedure:
1. Take 2 ml of solution that will be tested to the test tube
2. Add with 2 ml of NaOH and 10 drops of CuSO4
3. See the color of solution.