LC-MS/MS Determination of 15 Sex Hormones in Cosmetics

LC-MS/MS was applied to the determination of 15 sex hormones in cosmetics (cream, emulsion or water preparation). The sample (0.20 g) was dispersed in 2 mL of saturated NaCl solution and extracted twice with acetonitrile (2 mL each). 0.2 mL of each of the solution of 200 g·L^-1 K₄Fe(CN)₆ and 200 g·L^-1 (CH₃COO)₂Zn were added to the combined extract to precipitate the large molecular matrix. After centrifugation, the supernatant was taken and its volume was made up to 10 mL. Different programs were used in the gradient elution of estrogen hormones, male hormones and progestin hormones respectively, and in MS/MS analysis, the mode of ESI^- was applied to estrogen hormones and ESI⁺ was applied to male hormones and progestin hormones. Linear relationships between values of peak area and mass concentration of the 15 sex hormones were kept in the same range of 8.0-800 μg·L^-1, with detection limits (3S/N) in the range of 0.05-0.4 mg·kg^-1. Substantial samples of different batches were analyzed by this method, giving values of RSD's (n=6) in the range of 0.90% to 4.3%, and of recovery ranged from 80.3% to 121%.