Study And Application Of Estrogens-molecularly Imprinted Polymers Based On The Surface Of Functional-modified Magnetic Nano-silica

With the rapid development of human life and production activities, the residue of environment estrogens has harmed to human health. Especially estrogens have attracted more and more attentions in different research fields because of their strong biological activities. However, because of the low concentration of estrogens in samples, the interference of complex matrix components and the difference of separation, improving detecting sensitivity of trace estrogens in biological and environment samples is a major analytical challenge.In this research paper, the functional-modified method introducing more functional groups was proposed to modify the magnetic nanoparticles by the cross-over study of nanotechnology, magnetic separation technology, surface molecular-imprinting technology and dendrimers. And the estrogens-molecularly imprinted polymers based on the surface of functional-modified nanoparticles were synthesized for separating, enriching and detecting trace estrogens. We provided important theoretical foundation and applied basis of the study about magnetic surface molecularly imprinted polymers, and also provided an effective analysis method about the detection of hazardous substances from complex samples. The detailed novelty of this research can be categorized as following:1. The magnetic molecularly imprinted polymers for E2 (E2-MMIPs) were synthesized by using E2 as the template, the linear-grafting-modified magnetic nanoparticles with KH-570 as the supporter and MAA as the functional monomer. The results of extraction experiments showed that E2-MMIPs had some advantages including high adsorption capacity, quick binding kinetics and good selectivity for estrogens. Subsequently, E2-MMIPs were used as magnetic dispersive solid-phase extraction (MDSPE) sorbents coupled with HPLC-UV to successfully separate and detect the additive estrogens from the animal feeds and good recoveries were obtained. The detection results showed that E2-MMIPs had the superior ability to remove matrix interference. The amounts of estrogens (E2 and E3) which were detected from animal feeds were in the range of 2.68-3.06 mg kg-1 and 0.52-1.72 mg kg-1, and the average recoveries in the spiked samples were 92.7-97.0% and 71.9-83.1% with RSDs below 4.9%, respectively.2. Because the dendrimers have lots of functional groups advantage, magnetic molecularly imprinted polymers (MMIPs) were designed and synthesized by using 17-ethyl estradiol (EE2) as pseudo template with dendritic-grafting-modified magnetic nanoparticles as the supporter, avoiding residual template leakage and to increase the imprinting efficiency. The imprinted layer of MMIPs was controlled, ordered and high-density. The adsorption capacity of MMIPs (330.6 μmol g-1) was nearly three-fold that of MNIPs (107.3 μmol g-1). In addition, MMIPs had quick binding kinetics and good selectivity for estrogens. Meanwhile, MMIPs were used as MDSPE sorbents coupled with HPLC-UV for the detection of trace estrogens. The amounts of three estrogens (El, E2 and E3) which were detected from the plasma samples of pregnant women were 5.28,5.31 and 4.17 ng mL-1, and the average recoveries in the spiked samples were 87.8%-93.1% with RSDs below 6.3%, respectively. All these results revealed that MMIPs as MDSPE materials had good applicability to selective extraction and separation of trace estrogens from complex samples.