A novel fluorescent molecularly imprinted polymer SiO₂ @CdTe QDs@MIP for paraquat detection and adsorption

Paraquat (PQ) residue is harmful for human health, agriculture, and the aquatic environment. This paper proposes a novel fluorescent molecularly imprinted polymer (MIP), SiO₂ @CdTe QDs@MIP, for PQ detection and adsorption. The MIP was synthesized using 3-aminopropyltriethoxysilane as the functional monomer, 4,4'-bipyridyl as the template molecule, and tetraethoxysilane as the cross-linker. In addition, CdTe quantum dots featuring unique optical characteristics and excellent photochemical stability were combined as signal reporter. The synthesized MIP had a Brunauer-Emmett-Teller surface area of 68.2 m² /g, pore volume of 0.42 cm³ /g and pore size of 6.9 nm, demonstrating the potential for both PQ detection and adsorption. For PQ detection, the MIP could achieve three orders of magnitude better than the limit of detection, and one order of magnitude wider detection range than existing methods. The PQ recovery values for real samples of water and corn were 96.4-102.1% and 93.9-97.3%, respectively. The amount of PQ detected by the MIP was within 98.05% on average of that using high-performance liquid chromatography. For PQ adsorption, the MIP had an adsorption capacity of 3.36 mg/g, and followed a pseudo-second-order kinetic model with excellent toxicological characteristics. Overall, the novel SiO₂ @CdTe QDs@MIP proposed in this paper could facilitate an efficient and convenient method for PQ detection and adsorption.