Perovskite Quantum Dots for Fluorescence Turn-Off Detection of the Clodinafop Pesticide in Food Samples via Liquid–Liquid Microextraction

Herein, red fluorescent CsPbI3 perovskite quantum dots (PQDs) are successfully synthesized by a one-step reaction via a microwave irradiation method. The as-fabricated CsPbI3 PQDs displayed a strong emission intensity at 686 nm when applied with a λEx of 350 nm. The as-synthesized CsPbI3 PQDs were dispersed in hexane, and the quantum yield of CsPbI3 PQDs was 27%. The CsPbI3 PQDs were successfully integrated with liquid–liquid microextraction for the analysis of the clodinafop pesticide by fluorescence spectrometry. The emission peak of CsPbI3 PQDs at 686 nm was quenched (∼94%) by the clodinafop pesticide using hexane as a solvent, resulting in a dramatic change in fluorescence from red to nonfluorescence. The sensing mechanism was demonstrated by studying various techniques including fluorescence lifetime, high-resolution transmission electron microscopy, Fourier transform infrared spectroscopy, and density functional theory. The developed probe exhibited a good linearity over the concentration of clodinafop in the range of 0.1–5 μM with a limit of detection of 34.70 nM. The CsPbI3 PQDs could be used as a sensor for the quantification of clodinafop in vegetable, fruit, and grain samples. The developed method displayed good recoveries from 97 to 100% with lower relative standard deviations for the analysis of clodinafop in spiked samples, signifying that CsPbI3 PQDs could be used as a promising sensor for the detection of clodinafop in food samples.