Highly Efficient Selective Extraction of Chlorpyrifos Residues from Apples by Magnetic Microporous Molecularly Imprinted Polymer Prepared by Reversible Addition–Fragmentation Chain Transfer Surface Polymerization

Chlorpyrifos, as a moderate toxic organophosphorus pesticide, is prone to lingering in the environment and cannot be monitored easily. In this study, a magnetic, microporous, molecularly imprinted polymer was synthesized by using the reversible addition–fragmentation chain transfer polymerization method. The synthesized materials were properly characterized in terms of morphology, selectivity, and sorption capacity and used as sorbents for magnetic solid phase extraction for the selective determination of chlorpyrifos in apple samples. Results showed that the magnetic microporous molecularly imprinted materials were rough and porous spheres at an average size of 5 nm. The materials were highly selective toward chlorpyrifos with a superior sorption capacity of 167.99 mg·g^–1 and were resistant to the interference of competitive pollutants. After optimization, the recoveries of chlorpyrifos reached 96.2–106.5%, and the detection limit was 0.028 μg·kg⁻¹ by HPLC. Based on these analytical validation results, the developed method could be effective at determining chlorpyrifos in apples.