Benzoic acid, 5-​[2-​[4'-​[2-​[8-​[2-​[2,​4-​dihydroxy-​3-​[2-​(2-​methoxy-​5-​sulfophenyl)​diazenyl]​phenyl]​diazenyl]​-​1-​hydroxy-​3,​6-​disulfo-​2-​naphthalenyl]​diazenyl]​-​3,​3'-​dimethoxy[1,​1'-​biphenyl]​-​4-​yl]​diazenyl]​-​2-​hydroxy-​, sodium s