Fluorometric determination of ziram using CsPbBr₃ quantum dots

A strategy based on CsPbBr₃ quantum dots (QDs) is described for the determination of ziram pesticide. A facile and inert gas-free method was used for the synthesis of CsPbBr₃ QDs. The obtained CsPbBr₃ QDs displayed turn-off fluorescence behavior for ziram. The fluorescence intensity of the CsPbBr₃ QDs (E_x/E_m = 365/516 nm) was inversely proportional to the concentration of ziram (0.10 to 50.0 ppm) with a detection limit of 0.086 ppm. Notably, satisfactory recoveries (100 ± 0.25 to 107 ± 5.72%) were obtained in spiked fruit samples, which demonstrated that this method is capable of detecting ziram in real samples. In addition, the mechanism for the detection of ziram was investigated in detail. According to the results, this mechanism can be tentatively explained by fluorescence quenching originating from the increased surface defects and the structural changes of the CsPbBr₃ QDs. The detection ability of this strategy shows promising applicability in food safety.