Demonstration of oxidation dyes on human hair

This paper describes a method of selected ion monitoring (SIM) analysis which can demonstrate the staining of human hair with oxidation hair dyes. Hair samples were decomposed with NaOH-Na2S2O4 solution by heating (100 degrees C, 30 min) in a stream of nitrogen. Basic and neutral ether extracts from the reaction mixture were trifluoroacetylated with trifluoroacetic anhydride in ethyl acetate and were then analyzed by SIM. The minimum lengths of a single hair for the detection of the 5 components of oxidation hair dyes acting as indicators were 1 mm for toluene-2,5-diamine, 2 mm for p-phenylenediamine, 20 mm for p-aminophenol, 50 mm for m-aminophenol and 100 mm for o-aminophenol. This method was applied to practical cases and the results were good.