Ethanol, 2,2',2''-nitrilotris-, compd. with α,α'-[[[4-[[4-[2-[8-(acetylamino)-1-hydroxy-3,6-disulfo-2-naphthalenyl]diazenyl]-2,5-disulfophenyl](2-sulfophenyl)methyl]phenyl]imino]di-2,1-ethanediyl]bis[ω-hydroxypoly(oxy-1,2-ethanediyl)] sodium salt (1:1:4)