Swelling technique inspired synthesis of a fluorescent composite sensor for highly selective detection of bifenthrin

Abstract

Pesticide pollution has become a serious problem that threatens public health, so it is necessary to develop a method that can detect pesticides rapidly and sensitively. In this study, we report a novel fluorescent imprinted sensor based on quantum dots (QDs) synthesized via a facile and versatile swelling technique for highly selective detection of bifenthrin (BI). Compared with other fluorescent molecularly imprinted polymers (MIPs), it has three significant differences: firstly, polystyrene (PS) microspheres make up the polymer matrix and were prepared in advance; secondly, the interactions are not hydrogen bonding and covalent interactions, but van der Waals and hydrophobic forces; thirdly, aqueous QDs were successful applied to the swelling process using a polymerizable surfactant. The unique fluorescent sensor (MIPs (PS)-OVDAC/CdTe QDs) possesses the strong fluorescence and sensitivity of QDs and the high selectivity of molecularly imprinted polymers as well as a uniform morphology via this novel swelling strategy. As a result, the fluorescence intensity of the MIPs (PS)-OVDAC/CdTe QDs was strongly decreased within less than 25 min upon binding BI, and the quenching fractions of the MIPs (PS)-OVDAC/CdTe QDs presented a good linearity with BI concentrations in the range of 0.5–40 μM with a correlation coefficient of 0.9918. In addition, the limit of detection (LOD) was as low as 0.08 μmol L⁻¹ and a high imprinting factor of 4.11 was obtained. The developed method was successfully applied to the determination of BI in honey samples. The present study provides a facile and efficient strategy to develop fluorescent sensors for rapid recognition and selective detection of organic pollutants from complex matrices.