2-Naphthalenesulfonic acid, 6-((2,4-diaminophenyl)azo)-3-((4-((4-((7-((2,4-diamino-5-sulfophenyl)azo)-1-hydroxy-3-sulfo-2-naphthalenyl)azo)phenyl)amino)-3-sulfophenyl)azo)-4-hydroxy-, tetrasodium salt 6-((2,4-Diaminophenyl)azo)-3-((4-((4-((7-((2,4-diamino-5-sulfophenyl)azo)-1-hydroxy-3-sulfo-2-naphthalenyl)azo)phenyl)amino)-3-sulfophenyl)azo)-4-hydroxy-2-naphthalenesulfonic acid, tetrasodium salt 72987-18-9