Sagakauchi test



  • Arginine, the only amino acid containing the guanidium group, reacts with α - naphthol in presence of 10% NaOH and Sodium hypochlorite (oxidizing agent), to give a red colored product.
  • Non-amino acid compounds containing the guanidine group may also give a positive result.


  • To 3 ml of the protein solution add 1 ml of 10% NaOH and 1-2 drops of α - naphthol.
  • Mix thoroughly and add 4 drops of sodium hypochlorite.
  • A red color is formed.
  • This indicates the presence of arginine, which contains the guanidine group.
Last modified: Tuesday, 20 December 2011, 4:53 AM