Determination of 19 illegally added chemical ingredients in hair loss prevention cosmetics by ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry

Cosmetic products for hair loss prevention are often mixed with prohibited substances such as hormones, antibiotics, and forbidden pharmacologically active substances. Although drugs increase the efficacy of cosmetic products, they cause skin irritation and allergic reactions, upon long-term exposure. Given the increasing number of hair loss prevention cosmetics on the market, the need to guarantee product safety calls for efficient and reliable methods to identify illegal ingredients in these products. Chromatography combined with high-resolution mass spectrometry offers the advantages of high resolution and high throughout, thus being a powerful technique for simultaneously detecting illegal ingredients in cosmetics. In this study, an ultra-performance liquid chromatography-quadrupole-time of flight mass spectrometry (UPLC-Q-TOF-MS) method for detecting 19 illegal chemical components was established. Combined with the scientific database, a screening platform for hair loss prevention cosmetics was constructed. The effect of extraction solvent was investigated. The chromatographic and mass spectrometry conditions were optimized. Under the optimal conditions, separation was achieved within 20 min on an ACQUITY UPLC BEH C18 column (100 mm×2.1 mm, 1.7 μm). Acetonitrile and 2 mmol/L ammonium formate solution containing 0.05% formic acid were used as mobile phases for gradient elution. The 19 compounds were detected by positive ion electrospray ionization (ESI) in the MS mode. The chromatographic retention time, precursor ions, product ions of the target analytes, and abundance ratio were collected to construct a screening database with UNIFI software. The 19 compounds were well separated, with good linearity. The limits of detection (LODs) and limits of quantification (LOQs) were 0.025-0.05 μg/g and 0.075-0.15 μg/g, respectively. Hair lotion and shampoo, which are commonly marketed as hair loss prevention cosmetics, were selected as the respective matrices for the recovery experiment. The average recoveries of the 19 compounds ranged from 68.6% to 118.6%, and the relative standard deviations (RSDs) were 0.3%-10.3%. Then, 77 batches of cosmetic samples were detected and screened under the same conditions. The TOF-MS information, including the retention time, ion addition mode, mass-to-charge ratio of the parent ions and fragment ions, as well as the abundance ratio, were compared between the cosmetic samples and the standard MS information with UNIFI software.