Construction of hollow fiber stirring bar based on dummy molecularly imprinted polymers for the selective determination of organophosphorus pesticides in food samples

Abstract

In this study, the sol–gel method and layer-by-layer self-assembly technique were used to graft dummy template molecularly imprinted polymers (DMIPs) onto CG161M microspheres, yielding the DMIPs@CG161M composite, which was then applied as an adsorbent for detecting organophosphorus pesticides in food. A structurally analogous yet less toxic compound, diphenyl chlorophosphate, was employed as the dummy template to circumvent the detection interference arising from template leakage-a common drawback of traditional molecularly imprinted polymers-while also minimizing the safety risks associated with handling highly toxic pesticide standards during experimentation. The DMIPs@CG161M composite was immobilized on a hollow fiber stirring bar (HF-SBSE) to develop a solid-phase microextraction adsorbent. Combined with gas chromatography-mass spectrometry (GC-MS), a highly sensitive analytical method was developed for detecting organophosphorus pesticides in food samples. Under optimal conditions, the method exhibited good linearity for five organophosphorus pesticides-diazinon, parathion-methyl, fenitrothion, chlorpyrifos, and parathion-across a concentration range of 0.01–10 mg L⁻¹, with determination coefficients (R²) exceeding 0.9998. The limits of detection (LODs) and quantification (LOQs) ranged from 0.01 to 0.03 mg L⁻¹ and 0.03 to 0.11 mg L⁻¹, respectively. In the spiked food sample analysis, recovery rates ranged from 61.61% to 91.41%, with relative standard deviations (RSDs) between 4.01% and 6.91%. These findings indicated that the synthesized DMIPs@CG161M composite possessed excellent selective adsorption performance for organophosphorus pesticides in food samples, highlighting its potential as an efficient adsorbent for practical applications.