3-aminonaphthalene-2,7-disulphonic acid amino-R acid 3-aminonaphthalene-2,7-disulfonic acid Amido R acid 2,7-Naphthalenedisulfonic acid, 3-amino- 3-azanylnaphthalene-2,7-disulfonic acid 2-Aminonaphthalene-3,6-disulfonic acid 2-amino-3,6-naphthalenedisulphonic acid