Fluorescent probe of nitrogen-doped carbon dots derived from biomass for the sensing of MnO4- in polluted water based on inner filter effect

Nitrogen-doped carbon dots (N-CDs) were prepared from Auricularia auricula (L.ex Hook.) Underw via a one-step hydrothermal method. The N-CDs were spherical with an average particle size of 2.85 nm. The optimal excitation and emission wavelengths were 324 nm and 400 nm, respectively. There was considerable overlap between the excitation or emission spectrum of N-CDs and the UV absorption band of MnO4-. The inner filter effect (IFE) was formed between N-CDs and MnO4-, which led to the fluorescence quenching of N-CDs. The fluorescence quenching intensity of the system showed a good linear relationship with the concentration of MnO4- from 0.15 to 9.00 mu M, and the limit of detection (LOD) of MnO4- was 0.12 mu M. The proposed method was then used to measure MnO4- in polluted water with recoveries of 99.42 to 101.16%. The synthesized N-CDs offering trace MnO4- detection in simulation sample are extremely profound for environmental evaluation.