4-Amino- 3-hydroxy- 1-naphthalenesulfonic acid, 95.0+%

1-Amino- 2-naphthol- 4-sulfonic acid is a white to slightly brownish-pink powder. 1-Amino- 2-naphthol- 4-sulfonic acid, also known as 4-Amino- 3- hydroxy-1- naphthalene sulfonic acid, has a melting point of 290 °C. 1- Amino-2- naphthol-4- sulfonic acid is used in the determination of phosphates.