2,7-Naphthalenedisulfonic acid, 4-((4-((3,6-disulfo-1-naphthalenyl)azo)-1-naphthalenyl)azo)-3-hydroxy-, sodium salt 4-((4-((3,6-Disulpho-1-naphthyl)azo)-1-naphthyl)azo)-3-hydroxynaphthalene-2,7-disulphonic acid, sodium salt 83006-52-4 EINECS 280-102-1