Forensic chemical study on human hair. III. Identification of oxidative dyes and presumption of the brands from remaining components on human hair.

Abstract

Investigations were made on means of identifying the respective components of hair coloring preparations, especially oxidative dyes remaining on human hair. Thirty-four brands of oxidative dyes made by 11 manufacturers were identified by gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and thin layer chromatography (TLC) after extraction with ether. Components of 5 brands remaining on hair were identified by GC and GC-MS. The detection percentage was lowest among hair care products of both sexes. The 5 brands were grouped into 3 classes on the basis of components, and 2 of them were identified by characteristic peak (s) detected by GC and GC-MS. Oleyl alcohol, found in 3 brands, cetyl alcohol found in one and stearyl alcohol were common components of women's hair cream and hair treatment and hair rinse. The components of 16 brands were detected by TLC, and patterns of these brands fell into 3 classes. One brand among them was identified by characteristic patterns. Pyrolysis products of 5 brands (pyrolysis temperature 358°C) and of three brands (386°C) were recognized to be different from that of human hair by pyrolysis gas chromatography (PGC) and pyrolysis gas chromatography-mass spectrometry (PGC-MS). The different component was isopropanol. These results showed that if major components and isopropanol were detected from dyed hair by GC, GC-MS, TLC, PGC and PGC-MS, the brand of oxidative dye used on the hair could be identified.