Sensitive "On-Off" Fluorescent Sensor From N-Doped Carbon Dots for Fe Detection and Anticounterfeiting Applications.

Herein, a kind of N-doped fluorescent carbon dots (N-CDs) were prepared by using melamine and carboxymethyl cellulose (CMC) as precursors through a straightforward hydrothermal method. The designed sensor displayed a uniform nanoscale distribution, excellent hydrophilicity, and strong fluorescence emission with a fluorescence quantum yield of 37.98%. Moreover, the N-CDs could be utilized for Fe detection by the fluorescence "On-Off" transition via the mechanism of internal filtration effect (IFE) and static quenching process. Two good linear relationships within the concentrations of Fe from 10 to 100μM and 100 to 500 μM could be obtained, which indicated that the "On-Off" fluorescent sensor could quantitative analysis of Fe and the calculated detection limit (LOD) was 0.510 μM (3σ/slope). Additionally, the N-CDs could be used for the detection of Fe in the solid phase based on the fluorescence "On-Off" strategy, which is promising for anticounterfeiting application.