Synonyms: 2,7-Naphthalenedisulfonic acid, 4-amino-6-2,5-dimethoxy-4-2-(sulfooxy)ethylsulfonylphenylazo-5-hydroxy-3-4-2-(sulfooxy)ethylsulfonylphenylazo-;4-Amino-5-hydroxy-6-[4-(2-sulfooxyethylsulfonyl)-2,5-dimethoxyphenylazo]-3-[4-(2-sulfooxyethylsulfonyl)phenylazo]-2,7-naphthalenedisulfonic acid;5-Amino-4-hydroxy-3-[2,5-dimethoxy-4-(2-sulfooxyethylsulfonyl)phenylazo]-6-[p-(2-sulfooxyethylsulfonyl)phenylazo]-2,7-naphthalenedisulfonic acid