Determination of 41 Glucocorticoids in Cosmetics by Captiva EMR Solid Phase Extraction-High Performance Liquid Chromatography-Tandem Mass Spectrometry

A method was established for the simultaneous determination of 41 glucocorticoids in cosmetics by Captiva EMR solid phase extraction combined with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After the sample was dispersed by water, the target compounds were extracted with acetonitrile solution containing 1% (volume fraction) formic acid and Captiva EMR solid phase extraction column was used to remove long-chain hydrocarbons from the cosmetic matrix. In HPLC analysis, Thermo Accoure PFP chromatographic column was used as stationary phase, and mixed solution composed of acetonitrile solution containing 0.1% (volume fraction, the same below) acetic acid and 0.1% acetic acid solution was used as mobile phase for gradient elution. In MS/MS analysis, ESI⁺ mode and MRM mode were used for detection, and external standard method was used for quantification. It was shown that under the optimized test conditions, the six groups of isomers which were difficult to be separated in the target compounds could be separated effectively, and the matrix effect of cream, lotion, facial cleanser, gel and mask had a weak effect on most of the target compounds. Linear ranges of standard curves for 41 compounds found were all 1.5-100 μg·L^-1, with correlation coefficients of 0.993 4-1.000 and detection limits (3S/N) of 0.015-0.05 mg·kg^-1. The spiked recovery test was made on five matrices of cream, lotion, facial cleanser, gel and mask, giving recoveries in the range of 57.8%-121%, and RSDs (n=6) of determined values in the range of 0.50%-15%. The proposed method was applied for the analysis of the 60 batches of cosmetics, and 2 batches of positive samples were detected, with detection amount of 32.3 mg·kg^-1 for clobetasol propionate and 1.8 mg·kg^-1 for dexamethasone.