2,7-NAPHTHALENEDISULFONIC ACID, 3,3'-((3,3'-DICHLORO-4,4'-BIPHENYLYLENE)BIS(AZO) 2,7-Naphthalenedisulfonic acid, 3,3'-((3,3'-dichloro-4,4'-biphenylylene)bis(azo))bis(5-amino-4-hydroxy-, tetrasodium salt 47897-65-4 Afridol Blue tetrasodium salt