trisodium 7-[[2-(acetylamino)-4-[[(2,3-dichloro-6-quinoxalinyl)carbonyl]amino]phenyl]azo]naphthalene-1,3,6-trisulphonate

7-[[2-(Acetylamino)-4-[[(2,3-dichloroquinoxalin-6-yl)carbonyl]amino]phenyl]azo]-1,3,6-naphthalenetrisulfonic acid trisodium salt