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Abstract: In this paper, the molecularly imprinted polymer layer of estriol at the silica nanoparticles surface with selective recognition had been constructed. The methacryl groups of functional monomer at the silica nanoparticles surface were acted as reactive sites to induce imprinting polymerisation. The absorption capacity results showed that the molecularly imprinted polymers had an excellent combining affinity, recognition selectivity and fast kinetics. Furthermore, the molecularly imprinted polymers were successfully used as absorbent of dispersive solid-phase extraction coupled with high-performance liquid chromatography to determinate trace estriol and estradiol in milk tablets. The high recoveries yielded of 89.1–93.5% were achieved with the relative standard deviations less than 9.4%. So, the molecularly imprinted polymers are the effective absorbents for the separation and enrichment of oestrogens in the complex matrices samples. [Copyright &y& Elsevier]

Abstract: This paper reports a surface molecular self-assembly strategy for molecular imprinting on magnetic nanoparticles for selective separation and detection of estrogens in feeds. First, γ-methacryloxypropyltrimethoxysilane (MEMO) was successfully assembled at the surface magnetic nanoparticles through simple free radical polymerization, and subsequently, the copolymerization was further assembled between methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) in the presence of templates 17β-estradiol (E2). The synthesized magnetic molecularly imprinted polymers for E2 (E2-MMIPs) showed quick separation, large adsorption capacity, high selectivity and fast binding kinetics for E2. Meanwhile, a dispersive solid-phase extraction (DSPE) based on E2-MMIPs has been established for efficient separation and fast enrichment of estrogens from the feeds. The assay exhibited a linear range of 0.1–4μM for E2 and estriol (E3) with the correlation coefficient above 0.9996 and 0.9994, respectively. Recoveries of E2 from three kinds of feeds spiked at different concentration levels ranged from 92.7% to 97.0% with RSD<4.7%, and recoveries of E3 ranged from 71.9% to 83.1% with RSD<4.9%, respectively. The method is simple and sensitive, and can be used as an alternative tool to effectively separate and enrich the trace of estrogens in agricultural products by HPLC–UV. [Copyright &y& Elsevier]