disodium 4-hydroxy-3-[[3-methyl-4-[(4-sulphonatophenyl)azo]phenyl]azo]-6-(phenylamino)naphthalene-2-sulphonate

4-Hydroxy-3-[[3-methyl-4-[[4-[(sodiooxy)sulfonyl]phenyl]azo]phenyl]azo]-6-phenylamino-2-naphthalenesulfonic acid sodium salt