4-[3-(Chloroacetylamino)phenoxyacetylamino]-5-hydroxy-6-[2-(4-pentylphenoxy)phenylazo]-1,7-naphthalenedisulfonic acid disodium salt

disodium 4-[[[3-[(chloroacetyl)amino]phenoxy]acetyl]amino]-5-hydroxy-6-[[2-(4-pentylphenoxy)phenyl]azo]naphthalene-1,7-disulphonate