Abstract:

A method based on ultra-performance liquid chromatography-tandem mass spectrometry （UPLC-MS/MS） was established for the determination of 17 organic acids in cosmetics. Cosmetic samples were extracted with 50% （V/V） methanol-water solution. The sample solution was separated on a Welch Ultimate AQ-C₁₈ （2.1 mm× 100 mm, 1.8 μm） using 0.01% formic acid in water and methanol as the mobile phases under gradient elution. Mass spectrometry detection was performed in multiple reaction monitoring （MRM） mode. Qualitative analysis was based on retention time and relative abundance ratio of characteristic ion pairs, while quantitative analysis was carried out using the peak areas of quantitative ion pairs. Quantification was performed by the matrix-matched external standard method using calibration curves. For various matrix types, including creams, lotions, liquids, and gels, the 17 organic acids exhibit good linearity within their respective concentration ranges （R² > 0.99）. The limits of detection （LODs） range from 0.101 3-5.215 μg/g, and the limits of quantification （LOQs） range from 0.303 9-15.64 μg/g. At three spiked concentration levels （low, medium, and high）, the recoveries of the target analytes in different matrix samples range from 92.7% to 106%, with relative standard deviations （RSDs, n=6） of 1.5%-8.5%. This method features simple sample preparation, high analytical efficiency, high sensitivity, accurate quantification, and strong reproducibility, and is suitable for the determination of the 17 organic acids in various cosmetic products.

Key words: ultra performance liquid chromatography-tandem mass spectrometry, cosmetic products, organic acids