2-Naphthalenesulfonic acid, 7-amino-4-hydroxy-3-((4-(1-naphthalenylazo)-7-sulfo-1-naphthalenyl)azo)- 7-Amino-4-hydroxy-3-((4-(1-naphthalenylazo)-7-sulfo-1-naphthalenyl)azo)-2-naphthalenesulfonic acid 75627-25-7