Preparation Of Novel Sorbent And Development Of Detection Method Toward Environmental Estrogens

Environmental estrogens widely exist,and they have become the main way of endogenous estrogens into the human body.They are harmful to human body when they are accumulated to a certain amount.Therefore,development of a sensitive detection method is essential.In this study,a molecularly imprinted polymer with high selectivity was synthesized,and a sensitive method of molecularly imprinted on-line solid-phase extraction coupled with high performance liquid chromatography to detect the estradiol in the water sample was developed.The novel sorbent of modified chitosan was also synthesized.The main results include:1.Preparation and characterization of estradiol-molecularly imprinted polymerA molecularly imprinted functionalized sorbent for selective separation of estradiol was prepared by a surface imprinting technique in combination with sol-gel process,using estradiol as the template,?-aminopropyltrimethoxysilane as functional monomer,silica microsphere as the support material,and tetraethoxysilicane as cross-linker.Factors influencing polymerization were also discussed in detail.Results showed that the imprinted polymer exhibited higher adsorption capacity and selectivity toward the template molecule when the ratio between template,functional monomers and cross-linker was 1:3:8(mol/mol/mol).Results also indicated that the prepared polymer had fast uptake kinetics,22.0% of adsorption capacity was obtained within a short period of 10 min,and 99.3% of adsorption capacity was obtained within a period of 120 min,and the adsorption equilibrium was almost reached within 120 min.2.Molecularly imprinted on-line solid-phase extraction coupled with high performance liquid chromatography for determination of the estradiol in water sampleUsing the prepared polymer as sorbent,an effective separation and high sensitive method for determination of the estradiol was developed by molecularly imprinted on-line solid-phase extraction coupled with high performance liquid chromatography.Under optimal condition,the limit of detection(S/N=3)was 2.4 ng L-1.The enrichment factor was 490.The RSD for five replicate extractions of 0.05 mg L-1 estradiol was 5.96%.The accuracy and applicability of this presented method were evaluated by spiking experiment.Good recoveries of 88.9% to 101.1% were obtained for the blank river water spiked with 0.01 mg L-1,0.04 mg L-1,0.10 mg L-1 of estradiol.The lake water sample was quantitatively analyzed with estradiol at level of 0.17 mg L-1.3.Preparation and characterization of modified chitosanThe adsorption capacity of the prepared modified chitosan microsphere was best when the chitosan: ethyl acetate: 50% glutaraldehyde was 30:1:3(v/v/v).The modified chitosan exhibited a higher adsorption performance and faster adsorption dynamics towards estradiol,estriol and diethylstilbestrol.The adsorption capacity toward estriole was highest,and that toward diethylstilbestrol was lowest.