1,3-Naphthalenedisulfonic acid, 7-((4-((2-methyl-4-((sulfomethyl)amino)phenyl)azo)phenyl)azo)-, trisodium salt 68084-12-8 EINECS 268-424-0 Trisodium 7-((4-((2-methyl-4-((sulphonatomethyl)amino)phenyl)azo)phenyl)azo)naphthalene-1,3-disulphonate