Fluorescence detection of carbofuran in aqueous extracts based on dual-emission SiO₂ @Y₂ O₃ :(Eu³⁺ ,Tb³⁺ )@MIP core-shell structural nanoparticles

A novel double-windows fluorescence sensor for carbofuran (CF) detection was successfully developed based on rare-earth Eu,Tb-doped Y₂ O₃ @SiO₂ -based molecularly imprinted nanoparticles (MINs) with a multilayer core-shell structure. The recognition process of the MINs for CF was fairly fast and needed only ~8 min to reach a dynamic equilibrium. Interestingly, one fluorescence attenuation window was found with an increase in CF concentration (Q) from 0.1 to 10 μg ml^-1 and with a limit of detection (LOD) of 0.04 μg ml^-1 at 544 nm belonging to the Tb³⁺ emission, as well as another fluorescence enhanced window within the CF concentration range 10-100 μg ml^-1 (LOD = 4 μg ml^-1 ) at 617 nm of Eu³⁺ emission in the dispersed rare-earth-doped MIN colloidal aqueous solution. Luminescence resonance energy transfer from CF to Eu³⁺ and an inner filter effect of CF towards Tb³⁺ , as well from the two independent detection windows were clearly observed simultaneously. The competition experiment displayed hardly any marked interference during detection of CF following addition of its analogues (carbaryl, isoprocarb, aldicarb, methomyl, and etofenprox). Moreover, the MINs could also be applied to accurately detect CF in rhubarb and wolfberry samples with recoveries of 85.7-92.2%. This sensing system has high specific recognition and a wide detection range for CF and provides new opportunities for pesticide detection.