Determination of perfluoroalkyl carboxylic acids in mice serum and tissue by dispersive solid-phase extraction based on fluorine-functionalized covalent organic frameworks coupled with UPLC-MS/MS

Perfluoroalkyl carboxylic acids (PFCAs) are a class of persistent organic pollutants (POPs), which posed various hazards to organisms, including reproductive, developmental, neurological, and immunological toxicity. Consequently, developing an analytical method aimed at achieving highly sensitive detection of trace amounts of PFCAs in complex samples is clearly of great significance. Herein, the Fluorine-functionalized covalent organic framework (F-COF) was synthesized at ambient temperature, which has the advantages of high specific surface area (1297.7 m² g^-1), suitable selective adsorption pore size and good stability. Based on the multiple effects of suitable pore size, fluorine-fluorine interactions and hydrophobic interactions, F-COF exhibited high adsorption performance towards PFCAs. Accordingly, the method of F-COF-based dispersive solid-phase extraction (dSPE) coupled with UPLC-MS/MS was developed for the quantitative analysis of 5 PFCAs in complex biological samples. The results showed that the good linearity for the 5 PFCAs within the concentration ranges of 0.4 to 10⁴ ng L^-1, with correlation coefficients (r) all greater than 0.9993. The enrichment factors (EFs) ranged from 11.4 to 22.3 folds, and the limits of detection (LODs) were 0.11 to 0.17 ng L^-1. The established method provided a powerful tool for the enrichment and detection of PFCAs in mice serum and tissue. F-COF holds promising application prospects as a solid-phase extraction material for efficient enrichment separation and detection of PFCAs.