1-Amino-9,10-dihydro-9,10-dioxo-4-[[4-[(4-sulfophenyl)azo]phenyl]amino]-2-anthracenesulfonic acid

1-amino-9,10-dihydro-9,10-dioxo-4-[[4-[(4-sulphophenyl)azo]phenyl]amino]anthracene-2-sulphonic acid