Benzoic acid, 2-[[2-amino-5-hydroxy-6-[[4'-[[1-hydroxy-8-[[(4-methylphenyl)sulfonyl]amino]-3,6-disulfo-2-naphthalenyl]azo]-3,3'-dimethoxy[1,1'-biphenyl]-4-yl]azo]-7-sulfo-1-naphthalenyl]azo]-5-nitro-, trisodium salt