2,7-Naphthalenedisulfonic acid, 3-amino-4-((4-((2-(sulfooxy)ethyl)sulfonyl)phenyl)azo)- 3-Amino-4-((4-((2-(sulphooxy)ethyl)sulphonyl)phenyl)azo)naphthalene-2,7-disulphonic acid 56317-51-2 EINECS 260-108-0