Separation and determination of aminophenols and phenylenediamines by liquid chromatography and micellar electrokinetic capillary chromatography

The separation and determination of aminophenols and phenylenediamines were investigated by liquid chromatography (LC) and micellar electrokinetic chromatography (MEKC) in this study. Aminophenols and phenylenediamines are commonly used components in commercial hair colorants. The problem of tailing peaks in LC was improved by the technique of using mobile phase containing 15 mM triethylamine at pH 8.0. The analysis of o-aminophenol was not succeeded with LC even though the modifier of triethylamine was added. But it could be quantitative successfully by MEKC. The optimum separation condition of MEKC was achieved by employing 55 mM cetyltrimethyl ammonium chloride in 50 mM borate buffer (pH 9.2) with electric field strength of −145 V cm⁻¹. Finally, the commercial hair dyes were analyzed by developing methods of LC and MEKC. From both the results, there is no significant difference presence at 99.5% confidence level. These two methods could give the complementary results.