Selective extraction of methenamine from chicken eggs using molecularly imprinted polymers and LC-MS/MS confirmation

- Molecularly imprinted polymers for methenamine were prepared.
- The adsorption effects of the MIPs and NIPs for methenamine were investigated.
- A MIP-SPE purification method was coupled with LC-MS/MS to analyze methenamine in chicken eggs samples.
- The possible formation mechanism of MIPs for methenamine was discussed.

Molecularly imprinted polymers (MIPs) were synthesized as the selective sorbents for solid phase extraction (SPE), which was proposed for the determination of methenamine in chicken eggs by high performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The MIPs were prepared using methenamine as the template molecule, methacrylic acid (MAA) as the functional monomer and ethylene glycol dimethacrylate (EGDMA) as the cross-linker. The scanning electron micrograph was applied to characterize the morphologies of MIPs and non-imprinted polymers (NIPs), and the static and dynamic adsorption experiment were studied. The compositions and volume of the loading and eluting solvent were optimized. Linear calibration curve was obtained by chicken egg matrix-matched standard, within the range of 1.0-50.0 μg L−1 (R2 = 0.9983). The limit of detection (LOD) and limit of quantification (LOQ) were 0.6 μg kg−1 and 2.0 μg kg−1, respectively. Recoveries of methenamine in chicken eggs samples were in the range of 88.0%-112.8%. The relative standard deviation (RSD) of intra-day assay ranged from 2.3% to 8.7%, and inter-day assay ranged from 4.8% to 10.9%.