Further, examples of water-soluble organic solvents which may be contained in combination with these compounds represented by the formulae [I]-[III] may include alkyl alcohols having 1 to 4 carbon atoms such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol and the like; amides such as dimethylformamide,