A novel carbon dot-based fluorescence/UV dual-mode sensing method for the detection of organophosphorus pesticides

Abstract This study presents a fluorescence-colorimetric dual-mode method for the detection of organophosphorus pesticides (OPPs). The method exploits the fact that products of organophosphorus pesticides oxidized by potassium persulfate can both quench the fluorescence of carbon dots and induce color changes. Using Dimethoate (Dim) as the model analyte, the linear detection ranges for the fluorescence and colorimetric modes were 0.05–4.6 μ g ml −1 and 0.05–3.0 μ g ml −1 , respectively, with limits of detection of 0.027 μ g ml −1 and 0.0109 μ g ml −1 . The synergistic dual-mode response significantly enhances the reliability of the measurements. In spiked recovery tests using actual water samples, both detection modes demonstrated high recovery rates, confirming that the method maintains excellent accuracy and precision even in complex matrices. The dual-mode sensing probe developed in this study features a straightforward preparation process and achieves efficient, sensitive, and reliable detection of multiple OPPs, offering a promising analytical tool for monitoring pesticide residues.