LC-HRMS and Molecular Networking for Non-Targeted Screening of Emerging Contaminants in Cosmetics: Workflow, Applications, and Regulatory Challenges.

Emerging contaminants (ECs) in cosmetics are introduced through various pathways, including illegal adulteration, raw material impurities, and packaging migration. Characterized by chronic exposure, potential toxicity, and an elusive nature, these contaminants pose a continuous and serious threat to public health. Currently, the regulatory control of ECs in the cosmetics industry is still evolving. Traditional targeted analysis, which relies heavily on predefined reference lists and standards, suffers from narrow coverage and fails to meet modern safety requirements for the comprehensive screening and early warning of ECs. To address this challenge, liquid chromatography-high-resolution mass spectrometry (LC-HRMS), combined with non-targeted screening (NTS) strategies and molecular networking (MN), serves as a powerful analytical tool. By operating in a full-scan mode without predefined targets, this technology comprehensively captures thousands of chemical features in cosmetic samples, enabling the prioritization and tentative annotation of concealed risk substances for subsequent structural confirmation. Furthermore, the spectral similarity clustering capability of MN facilitates the identification of homologous derivatives and structural analogs from a single known compound, significantly enhancing the efficiency and systematic discovery of ECs. From a regulatory perspective, this integrated approach provides crucial technical support for authorities to accurately assess risks and ensure consumer safety. Ultimately, it promotes a paradigm shift in cosmetic safety management, from a passive response to known hazards to the proactive prevention and control of emerging risks.