Determination of aromatic amines in hair dye and henna samples by ion-pair extraction and gas chromatography–mass spectrometry

Abstract

A gas chromatography–mass spectrometry (GC–MS) method has been proposed for the determination of carcinogenic and toxic aromatic amines in hair dye, henna and dyed hair samples. The method includes ion-pair extraction of aromatic amines from aqueous samples with bis-2-ethylhexylphosphate (BEHPA) released after solving the samples in acidic solution followed by sonication, derivatisation of compounds with isobutyl chloroformate (IBCF) and their GC–MS analysis in both electron impact (EI) and positive and negative ion chemical ionisation (PNICI) mode as their isobutyloxycarbonyl ( isoBOC) derivatives. The obtained recoveries of aromatic amines ranged from 92.2 to 98.4% and the precision of this method, as indicated by the relative standard deviations (RSDs) was within the range of 0.7–4.2%. The detection limits obtained from calculations by using GC–MS results based on signal-to-noise ratio (S/N)= 3 were within the range from 0.02 to 0.20 ng/g. In the present study, the commercially available 54 permanent hair dye, 35 modified or natural henna and 15 dyed hair samples were analysed for the aromatic amines by the proposed method and the method was shown to be suitable to determine the aromatic amine ingredients and metabolites of these commercial products.