1-Naphthalenesulfonic acid, 4-((2,4-dihydroxyphenyl)azo)-3-hydroxy- 16623-47-5 4-((2,4-Dihydroxyphenyl)azo)-3-hydroxynaphthalene-1-sulphonic acid EINECS 240-672-4 NSC 87862 Sulfonaphtholazoresorcinol