Investigating the impact of novel brominated flame retardants (NBFRs) on metabolite and nutritional profiles in aquatic organisms by in vivo solid-phase microextraction (SPME)

• A cationic COF material was synthesized and utilized for in vivo SPME sampling for high coverage capture of metabolites from tilapia. • An SPME/HPLC-ESI-Orbitrap-MS method was established for non-targeted analysis. • Endogenous metabolites in the dorsal muscle tissue of tilapia altered significantly after seven days of NBFR exposure. • Some crucial nutritional components in tilapia like amino acids and their derivatives, glycosides, and lipid derivatives underwent significant changes. • NBFR exposure may compromise the nutritional value of the edible parts in tilapia. Novel brominated flame retardants (NBFRs), due to their ubiquitous environmental distribution in aquatic ecosystems and potential adverse effects to aquatic biota, have initiated global concerns. NBFRs were absorbed and bioaccumulated into aquatic organisms, impairing their growth while significantly disrupting metabolic and nutritional profiles deserves further elucidation, especially for in vivo and in situ characterization. In this study, we selected tilapia (Oreochromis mossambicus) as a model and developed an innovative in vivo sampling method using solid-phase microextraction (SPME) with a cationic covalent organic framework (COF) coating fiber, coupled with high performance liquid chromatography-electrospray ionization-Orbitrap mass spectrometry (HPLC-ESI-Orbitrap-MS) analysis. Our results demonstrated that self-made SPME fibers possessed excellent broad-spectrum extraction ability (totally 5250 molecular features were detected), and the developed analysis method has the advantages of greenness. SPME technology based on our self-made fiber was successfully applied in research of the impacts of NBFRs on tilapia. After statistical analysis, a total of 811 metabolites exhibited significant differential expression, including the nutritional components such as amino acids, glycosides, and lipids, which resulted in a decline in nutritional quality. These findings provided a new perspective for evaluating the ecological risk assessment of NBFRs, nutritional quality assessment of aquatic organisms and securing fishery products.