Synthesis and Evaluation of a Magnetic Molecularly Imprinted Polymer Sorbent for Determination of Trace Trichlorfon Residue in Vegetables by Capillary Electrophoresis

Abstract

AbstractIn this study, a magnetic molecularly imprinted polymer (MMIP) based on Fe3O4@SiO2@CdTe (CdTe@MMIP) was synthesized using trichlorfon as template molecule, methacrylic acid (MAA) as the functional monomer, and ethylene glycol dimethacrylate (EGDMA) as the cross‐linker. The prepared MMIP was characterized, and the results showed that it exhibited good recognition and selective ability, offered a faster kinetics for the adsorption of trichlorfon. Scatchard analysis indicated that the binding sites in the CdTe@MMIP had two distinct groups (the high and low affinity binding sites). The saturated adsorption capacity (Qmax1) was 63.2 mg/g due to the low affinity binding sites, and another saturated adsorption capacity (Qmax2) was 71.4 mg/g due to the high affinity binding sites. Using it as sorbent, a method of molecularly imprinted magnetic solid‐phase extraction coupled with capillary electrophoresis (MIMSPE‐CE) for selective extraction, magnetic separation, and fast determination of trace trichlorfon in vegetable samples was developed. Under optimal conditions, appreciable sensitivity was achieved with a LOD of 30 μg/kg (S/N = 3) for the developed method. The relative standard deviation (RSD) for five replicate extractions of 0.05 mg/L trichlorfon standard solution was 4.2%. To evaluate the accuracy of this method, the blank cucumber and cauliflower samples spiked with trichlorfon were extracted and analyzed by this method with good recoveries ranging from 78.7% to 96.6%. Moreover, this method was applied to the quantitative detection of the trichlorfon residues in rape samples, and the results correlated well with that obtained from the gas chromatography method.