Unlocking Enhanced Detection of Perfluoroalkanesulfonic Acids via Fluorinated Nonpolar 3D Covalent Organic Frameworks-Based Ambient Probe Nanoelectrospray Ionization Mass Spectrometry

The trace levels and severe matrix interferences greatly limited the determination of stable, persistent, and long-range-transported perfluoroalkanesulfonic acids (PFSAs) in complex environments. Here, we design and prepare the first fluorinated nonpolar 3D COF (TFPM-Pa-CF 3 ) as an adsorbent, consisting of tetrakis(4-formylphenyl)methane (TFPM) and 2,5-diaminobenzo-trifluoride (Pa-CF 3 ) for adsorption and extraction of PFSAs. The proposed TFPM-Pa-CF 3 demonstrates excellent adsorption capacity (509.1 mg g –1 ) and rapid adsorption kinetics (5 min) for PFSAs attributed to the synergistic effects of F–F, hydrophobic, and electrostatic interactions. Furthermore, TFPM-Pa-CF 3 is grown in situ on a stainless needle and coupled with ambient probe nanoelectrospray ionization mass spectrometry (PESI-MS) to develop a rapid and direct determination method with a low limit of detection (0.05–0.86 ng L –1 ) and wide linear range (1–10,000 ng L –1 ) for trace perfluorooctanesulfonate and its alternatives in environmental soil, algae and water. This work unlocks the efficient determination or removal of PFSAs in a complex environment, facilitating the solution of critical environmental PFSAs problems.