Preparation of molecularly imprinted polymers on the surface of magnetic carbon nanotubes with a pseudo template for rapid simultaneous extraction of four fluoroquinolones in egg samples

Fluoroquinolones (FQs) have emerged as one of the most important class of antibiotics. Due to their low concentration in bio-matrix samples which contain a lot of interfering substances, the efficient solid phase extraction and accurate determination of FQs remain a challenge. In this paper, a new strategy for the isolation and enrichment of FQs from egg samples was obtained by molecularly imprinted polymers on the surface of magnetic carbon nanotubes (MCNTs@MIP), which not only can be collected and separated rapidly by an external magnetic field, but also have a high specific surface area, outstanding mechanical properties and specific recognition for FQs. MCNTs@MIP were prepared using ofloxacin as a pseudo template, methacrylic acid as a functional monomer, and ethylene glycol dimethacrylate as a cross-linker. The characteristics of the MCNTs@MIP were assessed by transmission electron microscopy (TEM), multipoint Brunauer-Emmett-Teller (BET) analysis, vibrating sample magnetometry (VSM), X-ray diffraction (XRD) and Fourier transform infrared (FT-IR) spectroscopy. The results of the adsorption experiments not only demonstrated rapid dynamic adsorption but also showed a high selectivity toward FQs. An extraction method using MCNTs@MIP coupled with high performance liquid chromatography (HPLC) was developed for the determination of four FQs in egg samples. The recovery of four FQs ranged from 95.2% +/- 3.2% to 100.7% +/- 3.1% and the detection limits ranged from 0.25-0.40 ng g(-1). The results demonstrate that the proposed method based on pseudo template MCNTs@MIP is a promising approach for the preconcentration, purification, and simultaneous analysis of four FQs in bio-matrix samples.