A gas chromatographic analysis of α-naphthylamine (α-NH2), β-naphthylamine (β-NH2), α-naphthol and β-naphthol in cosmetic coal-tar colors has previously been described, in which the detection limit was reported to be 2ppm (Bulletin of National Institute of Hygienic Sciences, 89, 112, 1971)
Although it is desirable to develop the analytical method with a higher sensitivity judging from a recent public concern over the safety, Japan's Cabinet Order for the enforcement of the Labor Safety and Sanitation Law designated β-NH2 as a material not to be manufactured or processed and in addition, it is very likely in the future that the use of β-NH2 even as an experimental reagent will hardly be approved legally.
Thus, the separation of α- and β-NH2, the determination of the eluting position of β-NH2 by α-NH2, the relative sensitivity of β-NH2 to α-NH2, the calibration curve and detection limit were studied by using high speed liquid chromatograph (with fluorescence monitor) together with the clean-up procedure and the method was established for determining β-NH2 in cosmetic coal-tar colors with the detection limit of 5ppb by using α-NH2 as an alternate standard.
