Rapid handheld detection strategy for pyrethroid residues based on dual-channel fluorescence sensor

Herein, a dual-channel fluorescence sensor (Eu-NBDC@SiQDs) was constructed by integrating lanthanide metal-organic frameworks (Ln-MOF) with silicon quantum dots (SiQDs), and it was successfully used for rapid quantitation of one of type II pyrethroids’ metabolites, 3-phenoxylbenzaldehyde (3-PBD). After only 5-min incubation reaction, the fluoroprobe exhibited a distinctly ratiometric fluorescence variations, offering linear range of 0–10 μM and detection limit of 58.13 nM. Besides, the Eu-NBDC@SiQDs displayed strong anti-interfering effects on co-existing metal ions , other pesticides, and biomacromolecules in complex vegetable matrices. By optimizing the alkaline hydrolysis conditions, efficient hydrolysis of pyrethroids was achieved with percentage of > 90 %. Combined with time-dependent density functional theory (TD-DFT) calculations, the unique stepwise reaction mechanisms of Eu-NBDC@SiQDs were rigorously elucidated, providing new insights into the application of Ln-MOF materials in pesticide rapid detection. Integrating a self-developed portable fluorescence detector (PFD) with smartphone technology, this handheld instrument not only realized on-site and rapid detection of trace-level deltamethrin (Del) in lettuce, but also enhanced analytical stability and accuracy. Overall, the PFD-based handheld detection displays great application prospects because of its simple operation, low-cost and feasibility for outdoor assay. • Specific recognition of type II pyrethroids was achieved using the novel Schiff base method. • Quantitative detection of pyrethroids was realized through the construction of a dual-emission fluoroprobe. • The LOD of this method for type II pyrethroids reached 58 nM, which is much lower than the national standard. • The specific recognition mechanism was elucidated using TD-DFT calculations. • On-site rapid detection was achieved using a portable fluorescence instrument.