Handheld rapid analysis of pyrethroid residues using an ultralong Stokes shift fluorescent sensor

Monitoring pyrethroid residues is essential due to their environmental persistence and toxicity. However, conventional laboratory-based techniques are inadequate for real-time, on-site screening. Herein, we report the development of a novel coumarin-derived near-infrared (NIR) fluorescent probe featuring an ultralong Stokes shift of 330 nm, for the intelligent handheld detection of pyrethroids. Leveraging a twisted intramolecular charge transfer (TICT) to intramolecular charge transfer (ICT) transition mechanism, the probe achieves high-sensitivity turn-on response at 705 nm. In an optimized H 2 O/DMSO (19:1, v/v) system, the probe exhibited exceptional selectivity and anti-interference capability, with a limit of detection (LOD) of 1.33 nM. Furthermore, a portable fluorescence-to-vision transduction (FVT) integrating optoelectronic conversion and wireless communication was fabricated via 3D printing. This portable platform, connected to a smartphone via Bluetooth, enables automated data acquisition and concentration quantification. Spiked recovery assays in Kyoho grapes yielded results ranging from 98.36% to 100.83%, demonstrating high accuracy in complex matrices. This work not only provides a design strategy for ultralong Stokes shift NIR probes but also establishes a paradigm for handheld rapid analysis of pesticide.