Abstract:

A rapid screening and determination method was developed for eight nitrosamines in cosmetics by liquid chromatography-quadrupole-time-of-flight mass spectrometry. Cosmetics were well dispersed by saturated sodium chloride solution and extracted by vortex mixer using dichloromethane. After dichloromethane was dried under nitrogen, the residuums were redissolved by methanol; the separation of 8 target compounds was performed on an Agilent Poroshell 120 SB-C₁₈ column with gradient elution using methanol and water as mobile phases. Detection was achieved by atmospheric pressure chemical ionization in the positive mode, and rapid screening could be achieved using high-resolution mass spectrometry database which was created and acquired by Library view 1.3.1 software. Sample pretreatment methods were optimized, and the determination method for 8 nitrosamines in cosmetics was established through methodological study. The results showed that: this sample pretreatment method had purifying effect and had a better recovery compared with other pretreatment methods; the eight nitrosamines all showed good linear relationship （r≥0.999） in the range of 5-100 ng/mL under the optimized conditions; the average recoveries were in the range of 85.1%-113.1% at three spiked levels （0.03, 0.10, 0.50 mg/kg） with relative standard deviations （RSDs） of 1.4%-6.6%; limits of detection （LODs） were in the range of 0.001 0-0.020 0 mg/kg, and limits of quantitation （LOQs） were in the range of 0.003 0-0.060 0 mg/kg. This method was simple and timesaving for rapid screening of target compounds even in case of lack of standards, and the method also had high sensitivity and accuracy, which was suitable for trace detection of nitrosamines in cosmetics.

Key words: liquid chromatography-quadrupole-time-of-flight mass spectrometry, nitrosamine, rapid screening, cosmetics