Aggregation caused quenching of dual-emission nitrogen-doped carbon dots for visual quantitative and ratiometric detection of pesticide residues

High-performance and on-site detection of pesticide glyphosate (GLY) residue is particularly urgent and challenging. Herein, dual-emission nitrogen-doped carbon dots (N-CDs) synthesized from tris-hydroxymethyl-aminomethane and resorcinol are successfully developed as a ratiometric fluorescence sensor. Upon adding GLY, the fluorescence intensity of N-CDs at 425 nm is quickly quenched via aggregation-caused quenching and photoinduced electron transfer, leading to the complexation process of N-CDs with GLY. While the fluorescence intensity of N-CDs at 525 nm with little change can be served as the reference signal. This distinct ratiometric fluorescence sensor achieves the detection limit and quantification limit as low as 24 nM and 80 nM with a wide linear range of 0.024–30 μM, respectively. Moreover, a smartphone-integrated lateral flow visual sensing platform is established for GLY detection by capturing and identifying the parameters of color variations. This platform represents a potential for the quantitative monitoring of GLY residue in food and the environment.