In-situ growth of Eu-doped dual-functional fluorescent MOFs on glass vials: A portable platform for extraction and rapid detection of pyrethroid pesticides residues in tea.

Rapid detection of pyrethroid pesticide residues in food is critical to ensure human health. In this work, based on rationally-designed Eu-doped MOFs with dual functions of effective adsorption and fluorescent sensing to pyrethroid pesticides metabolite 3-phenoxybenzaldehyde, we designed a portable glass vials (GV) platform which can achieve simple separation and rapid determination of pyrethroid pesticides residues in food. Specifically, PCN-777 was in-situ grown on the inner surface of GV through rational ligand selection, followed by Eu3+ incorporation to construct a novel fluorescent composite (Eu-PCN-777@GV). The organic ligand of PCN-777 not only provides strong host-guest interactions with targets, but also efficiently sensitizes Eu3+ through "antenna effect", giving rise to intense red fluorescence emission. The hydrolysis product of pyrethroids 3-phenoxybenzaldehyde, significantly quenched the red fluorescence of Eu-PCN-777@GV through "inner filter effect". Combined with smartphone imaging, a portable fluorescent sensing platform was constructed, with detection limits 7.06 mg kg-1, 6.52 mg kg-1, and 8.04 mg kg-1 for lambda-cyhalothrin, permethrin and cypermethrin, respectively, and linear ranges of 10-200 mg kg-1. This method has been successfully applied to the extraction and detection of pyrethroid pesticides residues in tea. Spiked recoveries in samples ranged from 95.60% to 105.60%, showing high agreement with HPLC measurements. This work provides an integrated adsorption-detection platform for on-site pesticides analysis, featuring efficient analyte enrichment, rapid response, and good reusability. More importantly, it offers a design strategy to construct integrated adsorption-detection materials for broader application scenarios.