Nontarget screening and identification of emerging preservatives and their metabolites in human urine

Preservatives are widely used in cosmetic and personal care products to prevent microbial contamination and prolong products' shelf lives. However, concerns about human exposure to these chemicals are increasing due to their confirmed and/or potential negative effects on human health. In this study, we developed a nontarget and suspect screening strategy to identify 5 emerging preservatives and their metabolites in human urine using ultra-high performance liquid chromatography coupled with a high-resolution mass spectrometer (UHPLC-Q-Orbitrap HRMS). A workflow was established for metabolites identification by integrating m/z values of the parent preservatives with specific metabolic reactions. A total of 117 preservatives and relevant metabolites were tentatively identified in the urine samples collected from a general population of Guangzhou, China. p-hydroxyacetophenone (p-HAP) was the only detected parent preservative. Thirty metabolites with confidence levels (CLs) of 2 and 3 included 19 of p-HAP, 5 of dehydroacetic acid (DHA), 5 of caprylhydroxamic acid (CHA) and 1 of methylisothiazolinone (MIT). Sulfation, amino acid conjugation, and composite reactions were predominant metabolic pathways of the preservatives in human urine. This study presented a robust approach for screening and identifying emerging preservatives and relevant metabolites in human urine for comprehensive investigation of exposure and metabolism of preservative chemicals in human bodies.