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.