2,7-Naphthalenedisulfonic acid, 6-((2,4-diaminophenyl)azo)-4-hydroxy-3-((4-sulfo-1-naphthalenyl)azo)-, trisodium salt 69178-38-7 EINECS 273-902-7 Trisodium 6-((2,4-diaminophenyl)azo)-4-hydroxy-3-((4-sulphonato-1-naphthyl)azo)naphthalene-2,7-disulphonate