Abstract: A method for determination of propylene oxide in cleaning cosmetics by headspace gas chromatography/mass spectrometry (HS-GC/MS) was established.The influence of equilibrium temperature,equilibrium time and salts for propylene oxide measurement were investigated.Results showed that the better conditions are as follows:20.0 g of sample and 10.0 g of NaCl are added into 50 mL volumetric flask,and dilute with ultrapure water to 50 mL;transfer 5 mL of this solution to 22 mL headspace vial and mix with assistance of ultrasonic wave irradiation for 2 min,then the determination is to be carried out after the equilibrium at 80 ℃ for 10 min.The relationship between mass concentration and the corresponding peak area in the range of 0.1-10 mg/L shows good linearity (R²>0.999 9).The limit of detection is 0.002 5 μg/g and the limit of quantification is 0.005 μg/g.The average spiked recovery is >88%.

Key words: cosmetics, propylene oxide, HS-GC/MS