Abstract: A confirmatory method is presented for the determination of five nitro-musks (musk ambrette, musk xylene, musk moskene, musk tibeten and musk ketone) in different cosmetics by gas chromatography coupled with negative chemical ionization (NCI)-triple quadrupole mass spectrometry (GC-MS/MS). The samples were extracted under ultrasonication using a mixture of acetone and hexane. The extract was concentrated and then cleaned up by CNWBOND Si solid phase extraction cartridge. Five different instrument parameters such as the temperature programmed, ion source temperature, reagent gas pressure, collision energy, monitoring ion pairs were optimized for higher sensitivity. Then the analytes were qualitatively and quantitatively analyzed under the multiple reaction monitoring (MRM) mode after the chromatographic separation on an HP-5MS capillary column (30 m×0.25 mm, 0.25 μm), and employing d15-musk xylene as internal standard. The mixed standards were spiked in the blank cosmetics samples (each nitro-musk was about 500 ng/kg), and the recoveries were in the range of 85.81%~103.77% with the relative standard deviations (RSDs) not more than 5.32%. The limits of quantification of the method were about 50.0~500 ng/kg. The method is accurate, rapid, sensitive and can be used in the inspection of the five nitro-musks in cosmetics.

Key words: cosmetics, negative chemical ionization-triple quadrupole mass spectrometry, nitro-musks, gas chromatography (GC)