Molecular imprinting technology for the preparation of polymers with specific molecular recognition function had become one of the current research hotspots.

Three types of multi-walled carbon nanotubes (MWCNTs)/oxide reinforced hollow fibers, i.e. MWCNTs/SiO₂, MWCNTs/TiO₂, MWCNTs/ZrO₂, based on sol–gel techniques were fabricated, compared and applied to extract metronidazole in milk samples by solid phase microextraction (SPME) and gas chromatography-mass spectrometry (GC-MS). The factors influencing the extraction and desorption process were optimized, and the adsorption mechanism of MWCNTs/SiO₂ reinforced hollow fibers was briefly discussed. MWCNTs/SiO₂ reinforced hollow fiber might be selective to some organic compounds due to specific and non-specific adsorption of MWCNTs and SiO₂ nanoparticles. It was found that the method provided linear range from 0.01–1000 mg L⁻¹ (R = 0.9985), low detection limit of 0.01 mg L⁻¹, preferable recoveries (69–96%) at three different concentrations. The obtained results demonstrated that MWCNTs/SiO₂ hollow fiber solid phase microextraction could become a potential tool for quality control to monitor the amount of metronidazole residues in milk products.

This review illustrates the construction of a deep eutectic solvent (HBA & donor) and its use in synthesizing molecularly imprinted polymers via polymerization, with HBAs participating in imprinting target molecules.