Millon’s test


This test is very specific for tyrosine.


  • Amino acids having hydroxy benzene (tyrosine) react with mercury and mercuric nitrate present in the modified millon’s reagent to give a red colored complex.


  • To 1 ml of the protein solution add 5 drops of Millon’s reagent, heat for 30 sec. and cool.
  • A yellow precipitate is formed due to the combination of mercury with the –OH group of tyrosine present in the protein.
  • Now, add 5 drops of 1% sodium nitrite solution.
  • A brick red color is formed on nitration of the compound.
Last modified: Wednesday, 23 March 2011, 8:48 AM