Determination of 11 ultraviolet absorbents in sun-screening cosmetics by liquid chromatography-tandem mass spectrometry

A method of liquid chromatography-tandem mass spectrometry (LC-MS/MS) has been established for the simultaneous determination of eleven ultraviolet absorbents in sunscreening cosmetics. The cosmetic sample was extracted by methanol-ethanol-water (80: 10: 10, v/v/v). The extract was separated by reversed-phase high performance liquid chromatography on an Eclipse XDB-C18 chromatographic column (150 mm x 4.6 mm, 5 microm) with a gradient elution of acetonitrile and water containing 0.1% formic acid. The analyte was detected by MS/ MS with the multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention time and the relative abundance ratio of the characteristic ions, and quantitative analysis on calibration curve method. The research results showed that the limits of quantification (LOQ, S/N = 10) of the eleven ultraviolet absorbents ranged from 200 to 500 mg/kg and the average recoveries ranged from 77. 17% to 98.32% with the relative standard deviations from 2.40% to 11.11%. The method is suitable to detect the eleven ultraviolet absorbents in cream and milky sun-screening cosmetics.