Molecularly imprinted mesoporous silica incorporating C3N4 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 C 3 N 4 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 C 3 N 4 (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 −1 MG concentration range, and the detection limit is 10 ng·mL −1 . 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. Schematic representation of synthesis of molecularly imprinted mesoporous silica ratiometric fluorescent probes incorporating C 3 N 4 dots and CdTe quantum dots for determination of malachite green.