6-Amino-4-hydroxy-5-[[4-[[(4-methyl-2-sulfophenyl)amino]sulfonyl]phenyl]azo]-2-naphthalenesulfonic acid

6-amino-4-hydroxy-5-[[4-[[(4-methyl-2-sulphophenyl)amino]sulphonyl]phenyl]azo]naphthalene-2-sulphonic acid