Abstract: Aiming at the characteristics of perfluorinated chemicals (PFCs), including refractory nature, widespread occurrence in aquatic environments and aquatic organisms, as well as their adverse impacts on ecological environment and human health, paper spray ionization mass spectrometry (PS-MS) was employed to establish a non-invasive direct detection method for endogenous metabolites in tilapia epidermal mucus. Differential metabolites were screened by multivariate statistical analysis, and the mechanism of metabolic disorders was elucidated through database matching and pathway enrichment analysis. The optimized PS-MS method allowed direct and rapid detection of mucus samples, with an analysis time of ≤1 min per sample. A total of 44 differential metabolites were screened in positive ion mode and 40 in negative ion mode. These differential metabolites were mainly enriched in 15 metabolic pathways, covering amino acid metabolism, energy metabolism, lipid metabolism, and carbohydrate metabolism, confirming the metabolic disturbance by perfluorooctanoic acid in fish. This study verified that the PS-MS method can rapidly obtain the metabolic fingerprints of tilapia epidermal mucus under laboratory conditions, providing an effective approach for the non-invasive exploration of the biological metabolic effects of emerging pollutants.

Key words: paper spray ionization mass spectrometry, epidermal mucus, non-invasive detection, metabolomics