Hair dye ingredients in commercial oxidative hair dyes were determined by high performance liquid chromatography. Eight kinds of hair dye ingredients were well separated with reversed phase partition mode within 9 min, employing cyanopropylated Zorbax as a stationary phase and aqueous acetonitrile solution containing 1-heptanesulfonic acid as a mobile phase. Under these operating conditions, detection limits of individual hair dye ingredients were as follows. 2-Nitro-p-phenylenediamine, 4-nitro-o-phenylenediamine : 0.1 μg, o-aminophenol, m-aminophenol, p-aminophenol, p-phenylenediamine, resorcinol : 0.4 μg, toluene-2, 5-diamine : 1.0 μg. Silica gel column chromatography was applied for the separation of hair dye ingredients from contaminants (surfactant, hair protectant, and so on) in commercial hair dyes. Recoveries of individual hair dye ingredients were more than 95%. This method with cleanup procedure on a silica gel column was much suitable for the determination of hair dye ingredients in commercial oxidative hair dyes.
