trisodium 5-(acetylamino)-4-hydroxy-3-[[4-methoxy-3-[[2-(sulphonatooxy)ethyl]sulphonyl]phenyl]azo]naphthalene-2,7-disulphonate

5-(Acetylamino)-4-hydroxy-3-[[4-methoxy-3-[[2-(sodiosulfooxy)ethyl]sulfonyl]phenyl]azo]-2,7-naphthalenedisulfonic acid disodium salt