Facile green preparation of highly fluorescent nitrogen-doped carbon dots from bagasse for sensitive methyl parathion detection.

In this work, a high sensitivity fluorescence sensor system utilizing nitrogen-doped carbon dots (N-CDs) from bagasse was studied. A method was developed to examine methyl parathion (MP) via alkali hydrolysis. N-CDs were prepared via hydrothermal method from biomass bagasse. The maximum excitation band of the N-CDs was 370 nm, and the fluorescence quantum yield was 32.6 %. In a strong alkaline environment, the MP is hydrolyzed into p-nitrophenol via electrostatic interactions between inner filtration effect and molecules, which can inhibit the fluorescence of the N-CDs. The established MP-N-CD system has good linearity, with 0.005-10.0 μg·mL bound and a detection limit of 0.83 ng·mL. Then a fluorescence sensing system was used to detect MP in vegetable and fruit samples. The recoveries were between 98.2 % and 101.9 %, and relative standard deviation decreased to 3.6 %. The proposed method is green, simple, cost-effective, highly sensitive, and highly selective.