Novel photo-responsive deep eutectic solvents: preparation, characterization, and application in detecting organophosphorus chlorpyrifos pesticide residues in apples and grapes

Chlorpyrifos, an organophosphorus pesticide, poses health risks when present as a residue in fruits. This study reports the development of a novel photo-responsive deep eutectic solvent (PR-DES) for the sensitive and accurate detection of trace chlorpyrifos residues in fruit samples. The successful synthesis of PR-DES was confirmed by FT-IR, 1 H NMR, UV-Vis, and thermogravimetric analysis. By coupling PR-DES with UV-Vis detection, a green, cost-effective analytical method was developed for chlorpyrifos measurements, achieving a low limit of detection (16.19 μg L -1 ) and quantification (53.99 μg L -1 ).For spiked fruit samples, this method exhibited high average recoveries (98.6%-102.4%) and low relative standard deviations (0.63%-2.50%). Notably, chlorpyrifos can be hydrolyzed and removed post-analysis, whereas the photo-responsive component of PR-DES was recyclable, promoting sustainable chemical practices. This design strategy of PR-DES enriches the structural diversity and functional responsiveness of DES, thereby broadening their potential applications in analytical and environmental chemistry.