disodium 5-(acetylamino)-4-hydroxy-3-[[4-methyl-2-[(phenylsulphonyl)amino]phenyl]azo]naphthalene-2,7-disulphonate

5-(Acetylamino)-4-hydroxy-3-[[4-methyl-2-[(phenylsulfonyl)amino]phenyl]azo]-2,7-naphthalenedisulfonic acid disodium salt