Simultaneous determination of seven prohibited substances in cosmetic products by liquid chromatography-tandem mass spectrometry

In this paper, we developed and validated a simple, sensitive, and selective high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method to identify and measure the following prohibited substances that may be found in cosmetic products: minoxidil, hydrocortisone, spironolactone, estrone, canrenone, triamcinolone acetonide and progesterone. Chromatographic separation was performed on a Waters Symmetry C18 (100 mm × 2.1 mm, 3.5 μm particle size) with a gradient elution system composed of 0.2% (v/v) formic acid aqueous solution and methanol containing 0.2% (v/v) formic acid at a flow rate of 0.3 mL/min. The substances were detected using a triple quadrupole mass spectrometer in the multiple reaction monitoring mode with an electrospray ionization source. All of the calibration curves showed good linearity (r > 0.999) within the tested concentration ranges. The limit of detection was <25 pg. The relative standard deviations for intraday precision for each of the prohibited substances were <3.5% at two concentration levels (2 μg/g, 10 μg/g). The relative recovery rate for each of the prohibited substances ranged from 91.8% to 111% at three concentration levels (0.1 μg/g, 2 μg/g, 10 μg/g), including the limit of quantification. In conclusion, we have developed and validated a method that can identify seven prohibited substances in cosmetic products.