1,​5-​Naphthalenedisulfoni​c acid, 2-​[2-​[8-​[[4-​chloro-​6-​[[5-​hydroxy-​1,​7-​disulfo-​6-​[2-​[3-​[[2-​(sulfooxy)​ethyl]​sulfonyl]​phenyl]​diazenyl]​-​2-​naphthalenyl]​amino]​-​1,​3,​5-​triazin-​2-​yl]​amino]​-​1-​hydroxy-​3,​6-​disulfo-​2-​naphthalen