Simultaneous Determination of Seven Prohibited Substances in Cosmetic Products by Liquid Chromatography–Tandem Mass Spectrometry

The study developed and validated a high-performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) method to identify and measure seven prohibited substances (minoxidil, hydrocortisone, spironolactone, estrone, canrenone, triamcinolone acetonide, and progesterone) in cosmetic products. The method demonstrated good linearity (r > 0.999), a limit of detection <25 pg, and relative standard deviations for intraday precision <3.5%. The relative recovery rate ranged from 91.8% to 111% at various concentration levels. The method was applied to analyze 37 cosmetic products, revealing the presence of some prohibited substances in products purchased online, highlighting the need for improved supervision of internet-based cosmetic sales.