The oxine complex compounds of nickel and cobalt were extracted with organic solvent, such as methyl isobutyl ketone, amyl acetate, ethyl acetate or chloroform, and the extract was excited in the oxygen-hydrogen flame, and the line intensities of nickel and cobalt were measured at 352.4mμ and 352.7mμ respectively. The intensities of flame spectrum of these two elements were examined for each solvent under various conditions, and the sensitivity was found to be 10?30 times higher than that in aqueous solution.
Science reports of the Research Institutes, Tohoku University. Ser. A, Physics, chemistry and metallurgy 14 231-238, 1962