Synonyms: 2,7-Naphthalenedisulfonic acid, 3,3'-((3,3'-dimethoxy(1,1'-biphenyl)-4,4'-diyl)bis(2,1-diazenediyl))bis(5-amino-4-hydroxy-, sodium salt (1:?);2,7-Naphthalenedisulfonic acid, 3,3'-((3,3'-dimethoxy(1,1'-biphenyl)-4,4'-diyl)bis(azo))bis(5-amino-4-hydroxy-, sodium salt;3,3'-((3,3'-Dimethoxy(1,1'-biphenyl)-4,4'-diyl)diazo)bis(5-amino-4-hydroxynaphthalene-2,7-disulphonic) acid, sodium salt