Fluorescent Detection of Organophosphorus Pesticides Using Carbon Dots Derived from Broccoli

The determination of organophosphorus pesticide (OP S ) residues is of great significance to the evaluation and monitoring of food quality. In this study, nitrogen-, sulfur-, and silicon-co-doped carbon dots (CDs) were prepared from broccoli leaves and stems using a hydrothermal method and applied in fluorescent detection of organophosphorus pesticides. The prepared N-,   S- ,  Si -doped CDs are water-dispersible and hydrophilic with good fluorescent properties. It was found that fluorescence of the prepared CDs could be selectively quenched by Fe 3+ derived from Fe 2+ oxidation by hydrogen peroxide. A linear relationship between the fluorescence of CDs and concentration of Fe 3+ was established in a range of 0 − 200 µM, and its specific detection limit was 1.43 µM. CDs/Fe 2+ /acetylcholinesterase (AChE) fluorescent system was subsequently established to detect and quantify OPs residues in food samples based on the AChE inhibition strategy with a good linear range of 0.01 − 1.0 µM of O , O -dimethyl- O -2,2-dichlorovinyl phosphate (DDVP) concentration. A low detection limit of 8.0 nM was achieved. The hetero-atoms-doped CDs, which could be prepared from agro-wastes on a large scale, have great potential for the rapid real-time detection of OPs in authentic food samples with low detection values.