Analyses of Oxidative Dyes in Hair Dyes by High Performance Liquid Chromatography

Abstract

Three analytical methods of oxidative dyes in hair dyes have been developed by High Performance Liquid Chromatography (HPLC).
The first method, paired ion chromatography, employs octadecylsilica (TSK GEL LS-410, 5μ) as column, and as eluent, methanol (25v/v%) and the solution (75v/v%) prepared by dissolving 0.01M sodium octanesulfonate (counter ion) to 0.025M phosphate buffer adjusted to pH 2.5 with 5% phosphoric acid. The second method employs the same column as 1st method and as eluent, methanol and 0.1M phosphate buffer (pH 5.0) (10:90v/v%).
The third method employs as column μ-Bondapak CN (10μ) coated cyanopropylsilane, and as eluent ethanol and pentane (30:70v/v%).
The methods are not only accurate and convenient, almost no clean-up, but provides remarkable determination of p-phenylenediamine, o-, m-, and p-aminophenol and so forth, and the average recovery rate exceeds 95% (coefficient of variance; 2.6% maximun). The application of the techniques to hair dye products on the market showed good qualitative results with detecting almost no obstacle substance.