Abstract: A method for simultaneous determination of nine kinds of dyestuff in hair dyes by UPLC-MS/MS was established.The hair dye sample was extracted by methanol under assistance of ultrasonic irradiation.The separation was performed by a BEH-C₁₈ column (2.1 mm×100 mm,1.7 μm) with gradient elution of 10 mmol/L ammonium acetate and acetonitrile as mobile phase.The electrospray ionization (ESI) source with positive ion mode was used for the analysis of the nine components in the multiple reaction monitoring (MRM) mode.External standard method was used for quantification.The limit of detection of the nine kinds of dyestuff,including 2-(4-methyl-2-nitrophenylamino) ethanol,3-nitro-N-(2-hydroxyethyl)-4-aminophenol,4-amino-N,N-dimethylaniline,4-((2-hydroxypropyl) amino)-2-nitrophenol,bis-2,6-N,N-(2-hydroxyethyl) diaminotoluene,5-((2-hydroxyethyl) amino)-o-cresol,5-amino-6-chloro-2-methylphenol,3,5-diamino-2,6-dimethoxypyridine dihydrochloride and 6-amino-m-cresol are 1.7,0.84,0.27,3.4,0.034,1.2,7.0,0.17 and 0.20 mg/kg,respectively.The average recoveries of the nine kinds of dyestuff in the spiked samples are in the range of 90.0%-110.0% with the relative standard deviations (RSD,n=6) of 1.4%-8.6%.This method is simple,accurate and effective for simultaneous determination of the nine kinds of dyestuff in hair dyes.

Key words: hair dyes, dyestuff, ultra performance liquid chromatography-tandem mass spectrometry