Simultaneous Determination of Three Prohibited Bactericides in Anti-acne Cosmetics by Dispersive Solid-phase Extraction Followed by Gas Chromatography-Mass Spectrometry

KeyWord:dispersive solid-phase extraction(DSPE)  gas chromatography-mass spectrometry£¨GC-MS£©  prohibited bactericides  anti-acne cosmetics

Abstract:

      A gas chromatography-mass spectrometric method was developed for the simultaneous determination of three prohibited bactericides£¨chlorothalonil£¬myclobutanil and captafol£© in anti-acne cosmetics.Lotion-type cosmetic samples were injected for analysis after extracted with methanol and dried with anhydrous sodium sulfate.Grease-type cosmetic samples such as emulsion and cream were first demulsificated with sodium chloride£¬then extracted with methanol and dried using anhydrous sodium sulfate.As a following clean up step£¬dispersive solid-phase extraction£¨DSPE£© was utilized to minimize the interference of co-extracted substances.The chromatographic separation was performed on an HP-5MS£¨30 m¡Á0.25 mm¡Á0.25 ¦Ìm£© capillary column.The mass spectrometric analysis was conducted with electron ionization in selected ion monitoring£¨SIM£© mode.The characteristic fragment ions were used for qualification,and the external standard method was employed for quantitation.Under the optimized conditions£¬this method showed a good linearity£¨r2¡Ý0.997£© in the appropriate concentration ranges.The limits of detection£¨LODs£© for chlorothalonil£¬myclobutanil and captafol were 0.1£¬0.2,0.01 mg/kg£¬and the limits of quantitation£¨LOQs£© were 0.2£¬0.5,0.02 mg/kg£¬respectively.The recoveries of three analytes ranged from 80.5% to 111.3%£¬with relative standard deviations£¨RSDs£¬n=6£© of 1.8%-10.3%.The proposed method was validated with accuracy£¬reliability£¬simplicity and sensitivity£¬and could provide a scientific basis and technical support for the inspection and quality control of anti-acne cosmetics.