Development of high-luminescence perovskite quantum dots coated with molecularly imprinted polymers for pesticide detection by slowly hydrolysing the organosilicon monomers in situ

摘要

In spite of the high-brightness of perovskite quantum dots (QDs), their instability and sensitive to oxygen and moisture are still major challenges that obstruct their analytical applications. This work demonstrates the fabrication and application of perovskite CsPbBr3 QDs embedded in a molecularly imprinted polymer (MIP) for specific and sensitive detection of phoxim in real samples. CsPbBr3 QDs were obtained via a simple and convenient hot injection method. Based on the chemical structure of phoxim, we designed and synthesized a siloxane functional monomer with multiple functional groups to allow various types of interactions with phoxim. Next, the MIP/QDs composites were synthesized by slowly hydrolyzing the organosilicon monomers in situ. The obtained MIP/QDs composites possessed excellent selectivity for phoxim, and the imprinting factor of the optimized MIP/QDs was 3.27. Compared with previous studies regarding the detection of organophosphorus pesticides, the MIP/QDs fluorescence sensor exhibited high sensitivity and specificity. Under optimal conditions, the fluorescence quenching of the MIP/QDs had a good linear correlation for phoxim in the concentration range of 5-100 ng/mL, and with a limit of detection of 1.45 ng/mL. Finally, the method was used for the detection of phoxim in potato and soil samples, achieving recoveries of 86.8-98.2%.