Copper and nitrogen-doped carbon dots as an anti-interference fluorescent probe combined with magnetic material purification for nicotine detection

•An anti-interference fluorescent probe was developed for nicotine assay in tobaccos.•Fe3O4 nanoparticles were used to reduce the interference of coexisting substances.•Copper and nitrogen doped carbon dots was prepared via facile microwave method.•The combination of Fe3O4 adsorbent and fluorescent probe shows improved performance. In this work, a spectrofluorimetric method combined with magnetic solid-phase extraction purification was utilized for the nicotine detection in shredded tobacco. The copper and nitrogen doped carbon dots (Cu-NCDs) with a high quantum yield (30%) was prepared via facile microwave method and used as fluorescent probe for nicotine assay. Fe3O4 nanoparticles were used to remove the coexisting substances in the tobaccos by physical adsorption. The Cu-NCDs showed two fluorescence emission peaks at 294 nm and at 580 nm under a single excitation wavelength of 270 nm, and could be obviously quenched by nicotine at the same time. Herein, highly sensitive detection of nicotine in shredded tobacco was developed. Under optimal conditions, the fluorescence intensity of Cu-NCDs was linearly proportional to the nicotine concentration in the range of 0.1 to 10 μg mL−1, with the detection limit of 0.01 μg mL−1. The combination of Fe3O4 adsorbent and fluorescent probe showed improved anti-interference performance in comparison to fluorescent probe alone. Based on results from the study, the method could be utilized as a fluorescent probe for the practical determination of nicotine.