Selective recognition of tetracycline residues in animal derived samples based on molecularly imprinted microspheres from silica-stabilised Pickering emulsion polymerisation.

Novel molecularly imprinted polymers for selective binding of tetracyclines were synthesised through oil-in-water Pickering emulsion polymerisation with SiO2 particles as stabilisers. The products were used for solid phase extraction coupled with high-performance liquid chromatography to detect trace tetracycline and oxytetracycline in animal-derived samples. The SPE materials were characterised in detail by Fourier transform infrared spectrometry, scanning electron microscopy and thermogravimetry analysis. The imprinted polymers displayed high adsorption capacity, fast binding process and high selectivity through evaluation of adsorption performance employing kinetic, static adsorption and selectivity experiments. Under optimum detection conditions, good linearity (12 to 121 µg kg-1) and limits of detection (1.8 to 1.9 μg kg-1) for tetracyclines were obtained. In addition, satisfactory recoveries of 75% to 115 % were also achieved by spiking tetracyclines into milk, chicken, fish and pork samples, giving direct evidence of real practicality of our proposed separation method.