tetrasodium 7-[[4-[[4-[(sulphonatomethyl)amino]phenyl]azo]phenyl]azo]naphthalene-1,3,5-trisulphonate

7-[[4-[[4-[[(Sodiosulfo)methyl]amino]phenyl]azo]phenyl]azo]-1,3,5-naphthalenetrisulfonic acid trisodium salt