本文選題：功能化石墨烯　切入點(diǎn)：類濁點(diǎn)萃取　出處：《山東農(nóng)業(yè)大學(xué)》2017年碩士論文

【摘要】：汞及其化合物是廣泛存在于水體和食物中的一類有毒的重金屬污染物,它可以通過食物鏈在人體內(nèi)富集,危及人類健康。汞的毒性與其化學(xué)形態(tài)息息相關(guān),有機(jī)汞的毒性遠(yuǎn)遠(yuǎn)高于無機(jī)汞。然而,自然界的大多數(shù)的汞形態(tài)可以通過生物地球化學(xué)反應(yīng)轉(zhuǎn)化成毒性最大的甲基汞,特別是在水生環(huán)境中。因此,總汞的檢測已經(jīng)不能充分揭示汞及其化合物的生物有效性和毒性,汞形態(tài)分析對食品安全、人體健康以及相關(guān)毒理研究具有重要的意義。水體及大米中的汞污染一直受到人們的廣泛關(guān)注。但是,由于其含量較低,易受基質(zhì)干擾,汞形態(tài)分析方法的建立十分必要。本研究制備了兩種新型功能化石墨烯材料作為汞形態(tài)的高效吸附劑進(jìn)行樣品前處理,結(jié)合高效液相色譜-電感耦合等離子質(zhì)譜(HPLC-ICP-MS)開發(fā)富集和檢測汞形態(tài)的新方法,并進(jìn)行一系列的方法學(xué)驗(yàn)證。該方法成功地應(yīng)用于實(shí)際水樣和大米中汞形態(tài)的檢測,并探討了相關(guān)吸附機(jī)理。主要內(nèi)容如下:1.利用氧化石墨烯(GO)進(jìn)行有針對性地直接巰基化:氫溴酸與GO表面羥基和環(huán)氧基發(fā)生親核取代和加成反應(yīng),同時(shí)高溫處理造成脫水和局部脫溴;隨后,含有親核硫反應(yīng)中心的硫脲與溴基作用生成異硫脲鹽;堿處理水解生成直接巰基化石墨烯(G-SH)。利用透射電子顯微鏡(TEM)、傅里葉變換紅外光譜(FT-IR)、X-射線光電子能譜(XPS)等對G-SH進(jìn)行表征,用作汞形態(tài)的高效吸附劑。具有高分散性的G-SH可以形成類似于膠體的穩(wěn)定均勻的分散溶液,與傳統(tǒng)的濁點(diǎn)萃取相似,加入電解質(zhì)(NaCl)可以引起分散質(zhì)的聚集,從而分離吸附劑。該研究建立了基于G-SH為高效吸附劑的新型類濁點(diǎn)萃取(CPEL)技術(shù),并結(jié)合HPLC-ICP-MS開發(fā)了痕量汞形態(tài)檢測的新方法。本工作優(yōu)化了影響萃取效果的實(shí)驗(yàn)參數(shù),包括pH值、吸附劑的量、萃取時(shí)間、NaCl濃度、洗脫液的類型和濃度、干擾離子。在最佳實(shí)驗(yàn)條件下,無機(jī)汞(IHg)和甲基汞(MMHg)的檢出限(3δ)分別為3.8和1.3 ng·L-1,富集因子分別是78和77。該CPEL-HPLC-ICP-MS方法成功地應(yīng)用于實(shí)際水樣和大米中的汞形態(tài)分析。2.利用氧化石墨烯(GO)、乙酰丙酮鐵(Fe(acac)3)和乙二胺(EDA)在高溫高壓條件下,一步合成磁性還原氧化石墨烯(rGO-Fe3O4)。由于rGO表面氨基和Fe3O4NPs之間的共價(jià)相互作用,合成的rGO-Fe3O4具有較高的穩(wěn)定性,并且Fe3O4NPs的尺寸分布和覆蓋密度可以通過改變GO和Fe(acac)3的初始質(zhì)量比控制。雙硫腙作為高效的汞螯合劑與具有較高暴露面積的GO表面通過π-π相互作用簡易結(jié)合形成雙硫腙功能化磁性石墨烯(D@rGO-Fe3O4)。利用透射電子顯微鏡(TEM)、X-射線衍射光電子能譜(XPS)、振動(dòng)樣品磁強(qiáng)計(jì)(VSM)等進(jìn)行表征后,將其作為高效的磁性吸附劑,開發(fā)了磁性固相萃取技術(shù)(MSPE)結(jié)合HPLC-ICP-MS檢測痕量汞形態(tài)的新方法。對相關(guān)實(shí)驗(yàn)條件進(jìn)行了優(yōu)化,包括吸附劑的原料與比例、pH值、萃取時(shí)間、洗脫液的類型和濃度、洗脫時(shí)間、干擾離子。在最優(yōu)實(shí)驗(yàn)條件下,我們對MSPE-HPLCICP-MS方法進(jìn)行了方法學(xué)驗(yàn)證和實(shí)際水樣及大米的分析。無機(jī)汞(IHg)和甲基汞(MMHg)的檢出限(3δ)分別為0.48和0.17 ng·L-1,富集因子分別是400和380。相比于以前報(bào)道的檢測方法,該方法具有較便捷的前處理以及更高的靈敏度。
[Abstract]:Mercury and its compounds are widely present in a class of toxic heavy metal pollutants in water and food, it can be enriched through the food chain in the human body, endangering human health. Is closely related to the toxicity of mercury and speciation, the toxicity of organic mercury is far higher than that of inorganic mercury. However, since most of the speciation of mercury in natural world can be transformed into methylmercury toxicity the largest biogeochemical reaction, especially in the aquatic environment. Therefore, the detection of total mercury has been unable to fully reveal the bioavailability and toxicity of mercury and its compounds, mercury speciation analysis on food safety, is of great significance to human health and toxicology research. Mercury pollution and rice has been widely people's attention. However, because of its low content, prone to matrix interferences, mercury speciation analysis method. It is necessary to establish two new functions of this research prepared Graphene materials as efficient adsorption of mercury for sample pretreatment, combined with high performance liquid chromatography inductively coupled plasma mass spectrometry (HPLC-ICP-MS) to develop a new method of enrichment and detection of mercury, and a series of methods validation. This method is successfully applied to the actual water and mercury in rice. The adsorption mechanism was discussed. The main contents are as follows: 1. using graphene oxide (GO) for direct sulfhydryl of: hydrobromic acid and GO surface hydroxyl and epoxy nucleophilic substitution and addition reaction, and high temperature treatment caused by dehydration and partial debromination; then, containing thiourea and bromine the role of nucleophilic sulfur reaction center generated isothiuronium salts; alkali hydrolysis treatment of direct thiol graphene (G-SH) by transmission electron microscopy (TEM), Fu Liye transform infrared spectroscopy (FT-IR), X- ray photoelectron spectroscopy (XPS) on G -SH were characterized as efficient adsorbents for mercury speciation. With high dispersion of G-SH can be similar to the colloidal dispersion solution formed stable and uniform, similar to the traditional cloud point extraction, addition of electrolyte (NaCl) can cause dispersion aggregation, thereby separating the adsorbent. The study is established based on G-SH for efficient adsorbent the new class of cloud point extraction (CPEL) technology, a new method and combined with the development of HPLC-ICP-MS detection of Trace Mercury form. The optimized experimental parameters affecting the extraction efficiency, including pH value, adsorbent amount, extraction time, NaCl concentration, type and concentration of eluting liquid, interfering ions at the optimal condition. (IHg), inorganic mercury and methylmercury (MMHg) detection limit (3 D) were 3.8 and 1.3 ng - L-1, the enrichment factor were.2. 78 and 77. of the mercury speciation analysis CPEL-HPLC-ICP-MS method is successfully applied to the actual water samples and in Rice The use of graphene oxide (GO), iron acetylacetonate (Fe (ACAC) 3) and ethylenediamine (EDA) in high temperature and high pressure conditions, one step synthesis of magnetic reduction of graphene oxide (rGO-Fe3O4). Due to the interaction between rGO and Fe3O4NPs on the surface of amino covalent synthesis of rGO-Fe3O4 has high stability, and Fe3O4NPs the size distribution and coverage density can be changed by GO and Fe (ACAC) 3 of the initial mass ratio control. Dithizone as mercury chelator efficient and high surface area exposed to GO through pi pi interactions with simple form of dithizone functional magnetic graphene (D@rGO-Fe3O4) using transmission electron microscopy. (TEM), X- ray photoelectron spectroscopy (XPS), vibrating sample magnetometer (VSM) were characterized after the effective magnetic adsorbent, developed magnetic solid phase extraction (MSPE) combined with HPLC-ICP-MS new form of detection of Trace Mercury Method. The related experimental conditions were optimized, including raw materials and the proportion of adsorbent pH value, extraction time, type and concentration of eluent, elution time and interference ions. Under the optimum conditions, we analyzed the method validation and actual water sample and rice on the MSPE-HPLCICP-MS method of inorganic mercury (. IHg) and methylmercury (MMHg) detection limit (3 D) were 0.48 and 0.17 ng L-1 respectively, the enrichment factor detection method is 400 and 380. compared to the previously reported, this method has the advantages of convenient pretreatment and higher sensitivity.

【學(xué)位授予單位】：山東農(nóng)業(yè)大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：O657.63;TS207.51

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