disodium 4-amino-5-hydroxy-6-[[4-methyl-3-[(phenylamino)sulphonyl]phenyl]azo]-3-[(4-nitrophenyl)azo]naphthalene-2,7-disulphonate

4-Amino-5-hydroxy-6-[[4-methyl-3-[(phenylamino)sulfonyl]phenyl]azo]-3-[(4-nitrophenyl)azo]-2,7-naphthalenedisulfonic acid disodium salt