tetrasodium 4-(benzoylamino)-5-hydroxy-6-[[1-sulphonato-6-[[2-(sulphonatooxy)ethyl]sulphonyl]-2-naphthyl]azo]naphthalene-1,7-disulphonate

4-(Benzoylamino)-5-hydroxy-6-[[1-(sodiooxysulfonyl)-6-[[2-(sodiooxysulfonyloxy)ethyl]sulfonyl]-2-naphthalenyl]azo]-1,7-naphthalenedisulfonic acid disodium salt