73507-23-0 EINECS 277-497-8 Tetrasodium (mu-(7-((4'-((8-amino-1-hydroxy-3,6-disulpho-2-naphthyl)azo)-3,3'-dihydroxy(1,1'-biphenyl)-4-yl)azo)-8-hydroxynaphthalene-1,3-disulphonato(8-)))dicuprate(4-)