Molecularly imprinted mesoporous silica incorporating CN dots and CdTe quantum dots as ratiometric fluorescent probe for determination of Malachite Green.

A new dual-emission ratiometric fluorescent probe was synthesized and successfully used for the determination of Malachite Green (MG) in fish farming water. The ratiometric fluorescent probe was successfully composited by sol-gel method using CN and CdTe quantum dots as fluorescent materials combined with mesoporous molecularly imprinted polymers. MG quenches the red fluorescence of the CdTe QDs (with excitation/emission wavelengths at 350/680 nm) while the blue fluorescence of CN (with excitation/emission wavelengths at 350/458 nm) remains unchanged. The change of fluorescence color and fluorescence intensity ratio can be successfully used for quantification of malachite green. In addition, the mesoporous structure has a large surface and good adsorption capacity for malachite green. The normalized intensity of fluorescence increases linearly in the 50-1000 ng·mL MG concentration range, and the detection limit is 10 ng·mL. The imprinting factor is 3.2. The nanoprobe was applied to the determination of MG in fish farming water samples. Recoveries and relative standard deviations were 92.5-97.8% and 2.5-6.2%, respectively. Graphical abstract Schematic representation of synthesis of molecularly imprinted mesoporous silica ratiometric fluorescent probes incorporating CN dots and CdTe quantum dots for determination of malachite green.