| With the rapid development of science and technology,analysis science is facing new opportunity and rigorous challenge.Sensitive,rapid,reproducible,simple and accurate analytical methods are required for the determination of trace components in geological,biological and environmental samples.Although many instrument analysis methods possessing higher sensitivity and selectivity have been developed recently, pre-concentration and analysis of trace elements is still necessary before the more accurate measurement by analytical instruments in reality.The pre-concentration and analysis of trace elements will depend on different adsorption materials with higher selectivity and bigger adsorption capacity and appropriate separation methods.In this research paper,several new adsorption materials are synthesized in order to pre-concentration and separation of trace components.Their adsorption and selectivity characteristics for trace components have been investigated systematically. The more detailed novelty of this research can be categorized as following:1.p-Toluenesulfonylamide as functional group was immobilized on silica gel and nanometer SiO2.Their adsorption efficiency toward metal ions was investigated by the batch equilibrium technique.Although silica gel and nanometer SiO2 has the same composition(silicon and oxygen),the difference of their sizes and surface structures result in the distinct chemical activity and selectivity.At pH 4,the adsorption capacity of modified silica gel adsorbent was found to be 4.9 mg g-1,5.0 mg g-1,33.2 mg g-1,and 12.6 mg g-1for Cr(Ⅲ),Cu(Ⅱ),Pb(Ⅱ)and Zn(Ⅱ),respectively. However the adsorption capacity of nanometer SiO2 adsorbent toward Cr(Ⅲ)was 26.7 mg g-1.The potential application of p-toluenesulfonylamide-modified silica gel for simultaneous preconcentration of trace chromium,copper,lead and zinc from two standard reference materials and two food samples was performed with satisfactory results. 2.The imprinted and non imprinted amino-functionalized silica gel adsorbent for Cr(Ⅲ)and Zn(Ⅱ)was obtained by a surface imprinting technique for selective solid-phase extraction(SPE)of Cr(Ⅲ)and Zn(Ⅱ)prior to its determination by ICP-AES:(1)The imprinted amino-functionalized silica gel adsorbent exhibited excellent selectivity and rapid kinetics process for Cr(Ⅲ).The relatively selectivity factor(ar)of Cr(Ⅲ)/Co(Ⅱ),Cr(Ⅲ)/Au(Ⅲ),Cr(Ⅲ)/Ni(Ⅱ),Cr(Ⅲ)/Cu(Ⅱ),Cr(Ⅲ)/Zn(Ⅱ), was 377,21.4,15.4,27.7,26.4,respectively.Under the optimal condition,Cr(Ⅲ)can be absorbed quantitatively but Cr(Ⅵ)was not retained.Total chromium was obtained after reducing Cr(Ⅵ)to Cr(Ⅲ)with hydroxyammonium chloride.The detection limit (3σ)for Cr(Ⅲ)was 0.11 ng mL-1.The relative standard deviation(R.S.D.)was 1.2%. The proposed method has been validated by analyzing two certified reference materials and successfully applied to the determination and speciation of chromium in natural water samples with satisfactory results.(2)Comparing with the traditional solid sorbents and non-imprinted sorbent,zinc(Ⅱ)-imprinted sorbent have higher selectivity and adsorption capacity for Zn(Ⅱ).The selectivity coefficient of the zinc(Ⅱ)-imprinted sorbent for Zn(Ⅱ)in the presence of Hg(Ⅱ)was 147.The relatively selective factor(αr)values of Zn(Ⅱ)/Hg(Ⅱ)were 15.5,which were greater than 1.The distribution ratio(D)values of zinc(Ⅱ)-imprinted polymers for Zn(Ⅱ)were greatly larger than that for Hg(Ⅱ).The detection limit(3σ)of the method was 0.29μg L-1.The proposed method was applied to the determination of trace zinc in biological and water samples with satisfactory results.3.A new functional monomer N-(o-carboxyphenyl)maleamic acid was synthesized and chosen for the preparation of surface-grafted ion-imprinted polymers (IIPs)specific for thorium(Ⅳ).Polymerizable double bond was introduced to silica gel surface by amidation reaction between -NH2 and maleic anhydride.The obtained imprinted particles exhibited excellent selectivity and rapid kinetics process for Th(Ⅳ).The relatively selective factor(αr)values of Th(Ⅳ)/La(Ⅲ),Th(Ⅳ)/Ce(Ⅲ), Th(Ⅳ)/Nd(Ⅲ),Th(Ⅳ)/U(Ⅵ)and Th(Ⅳ)/Zr(Ⅵ)were 85.7,88.9,26.6,64.4 and 433.8,which were greater than 1.The detection limit(3σ)and the quantification limit (10σ)of the method was 0.51 ng mL-1and 1.19 ng mL-1,respectively.The prepared IIPs as solid-phase extractants were successfully applied for the preconcentration of trace thorium in natural and certified samples prior to its determination by inductively coupled plasma atomic emission spectrometry(ICP-AES)with satisfactory results.4.A 4,5-Dibromofluorescein imprinted polymer was prepared by traditional imprinting technique using acrylamide as monomer.Quercetin imprinted silica gel was prepared by surface imprinting technique using methacylic acid and acrylamide as monomer,respectively.The imprinted polymer obtained was investigated in equilibrium binding experiments to evaluate the molecular recognition and binding characteristics of the 4,5-Dibromofluorescein and quercetin molecularly imprinted polymer.The substrate selectivity of imprinted polymer and non-imprinted polymer was investigated.The results showed that the imprinted polymer exhibited much higher affinity for 4,5-Dibromofluorescein and quercetin among the tested compounds. It is possible to be a good adsorption and binding material in the selective enrichment and determination of trace 4,5-Dibromofluorescein and quercetin in complex biosamples.
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