Nitrogen-doped carbon dots as efficient turn-on fluorescent probe for assay of organophosphorus pesticides

Concerns regarding human health and food safety have generated interest in developing simple, accurate, and cost-effective strategies for evaluating organophosphorus pesticide (OP) residues. In this study, nitrogen-doped carbon dots (N-CDs) were synthesized from a common low-cost precursor via a simple pyrolysis process. The fluorescence of the N-CDs can be suppressed by p-nitrophenol, which is the hydrolysis product of the p-nitrophenyl phosphate salt catalyzed by alkaline phosphatase (ALP). A fluorescent turn-on assay for the inhibitory effect of glyphosate was developed with a low detection limit and wide linear range. Moreover, the feasibility of visualizing OPs in vegetables was demonstrated by the fluorescence imaging of glyphosate on cabbage leaves. This research not only offers a facile method for the synthesis of highly fluorescent CDs but also inspires the development of effective multi-mode sensing platforms that include fluorescent testing and imaging for monitoring pesticide residues.