Fluorescent and visual detection of methyl-paraoxon by using boron-and nitrogen-doped carbon dots

Methyl-paraoxon (MP) is a representative organophosphorus pesticide (OP), which is a huge threat to the safety of human beings. In this study, carbon dots doped with boron and nitrogen (B, N–CDs) were used as a fluorescent probe for MP detection. The prepared cerium oxide (CeO 2 ) decompose MP efficiently into p-nitrophenol (p-NP) and phosphate group in the alkaline condition. The dissociative p-NP could reduce the fluorescent intensity of B, N–CDs through the inner filter effect (IFE). The pH value, incubation time, the amount of B, N–CDs and solvent effect were investigated and optimized for detection system. Under the optimum conditions, the limit of the detection was calculated to be 24.7 ng mL −1 with simple procedures. Tap water, lake water, Semen Coicis and Panax quinquefolius L. samples were used to test the recoveries of the detection system. The recoveries ranged from 94.68% to 107.28%. Furthermore, the fluorescence laminate was developed by painting B, N–CDs on the polyamide laminate. The MP residue could be observed directly under the 365 nm lamp, and linearity for MP by using the fluorescent laminates was ranged from 0.015 to 1.5 mM. The present work provides a rapid and dual-signal based method (fluorescent and visual) for routine detection of MP in real samples.