pH-responsive dual-emission carbon dots for the ratiometric detection of organophosphorus pesticides in Brassica chinensis and Hg2+ in water

Accurate and rapid monitoring of organophosphorus pesticides (OPs) residues is crucial for regulating food safety. Herein, dual-emission carbon dots (de-CDs) were fabricated for the ratiometric detection of OPs and Hg 2+ . The de-CDs exhibited two emission peaks at 678 and 485 nm when excited with visible light. Interestingly, the fluorescence at 678 nm was significantly quenched by Hg 2+ mainly because of the static quenching effect, whereas that at 485 nm exhibited a slight change. More significantly, the quenched fluorescence of the de-CDs recovered remarkably after introducing omethoate , diazinon and malathion . Accordingly, the ratiometric detection of the three OPs and Hg 2+ was achieved with high selectivity and robust performance. In addition, the OPs residues assay in Brassica chinensis was successfully performed with satisfactory results. This study not only provides an attractive tool for the simple and rapid assay of OPs but also offers new insights into the fabrication of multi-functional carbon dots .