Flavonoid dyes with molecular packing-induced fluorochromism for ratiometric broad-spectrum detection of avermectins

The widespread use of avermectins (AVMs) pesticides has sparked concerns regarding environmental contamination and potential risks to human health. There is a pressing need for effective analytical tools that can accurately and rapidly detect AVMs on-site, however, which is currently lacking. In this study, we introduce a series of flavonoid probes, for the first time, that exhibit a rapid, sensitive, selective, and broad-spectrum fluorescence response to AVMs. The presence of AVMs triggers a change in molecular packing modes of the probe aggregates in aqueous solutions, thus leading to a drastic emission color shift from red to yellow. Furthermore, by harnessing paper-based testing strips and 3D-printed testing devices, this method is successfully applied in portable on-site determination of AVMs in various food and environmental matrices. Overall, this approach addresses critical limitations in AVM detection by providing a promising analytical tool that may inspire more probe design for environment analysis.