【作者】 崔飞；

【导师】 张晓丽；

【作者基本信息】 山东大学 ， 分析化学， 2013， 硕士

【摘要】 实验中根据不同的实验需求对石墨烯进行了功能化或改变了石墨烯修饰电极的制备方法,不但改善了石墨烯的分散性,而且赋予了石墨烯某些新的特性。主要研究内容如下：1.借助氧化石墨烯上的羧基、环氧基和羟基,可以不通过其它连接剂使纳米金附着在石墨烯片层上。实验中以氧化石墨烯和氯金酸为反应物,采用水相共还原法制备了石墨烯／纳米金复合材料。通过功能化解决了石墨烯不易分散、易团聚等问题。与裸电极比石墨烯／纳米金复合材料对肾上腺素具有更高的灵敏度和催化能力。线性范围是5.0×10-8～8.0×10-6mol L-1,在信噪比为3的情况下检测限为7.0×10-9mol L-1。而且该复合材料对其他生物小分子也有较大的响应信号,在分析检测中具有潜在的应用价值。2.离子液体不但可以作为石墨烯／纳米金复合材料的分散介质,在构建的传感器中还起到增敏作用。将分散于离子液体中的石墨烯／纳米金复合材料修饰到电极表面,将氧化还原媒介体硫堇通过键合作用固定到修饰电极表面,构建了一种无酶型过氧化氢传感器。线性范围是4.0×10"6～2.9×10-3molL-1,检出限为4.3×10-7molL-1(S/N=3)。3.由于氧化石墨烯中含氧官能团的存在,使得氧化石墨烯片层之间因为电荷斥力的影响能在水中稳定分散,不易发生堆积。实验中,以氧化石墨烯的水溶液为沉积液,用电化学方法将氧化石墨烯还原成石墨烯,并同步沉积到玻碳电极上,制备了电沉积石墨烯修饰电极。茶碱在电沉积石墨烯修饰电极上具有较高的响应信号,线性范围是8.0×10-1检出限为6.0×10-7mol L-1(S/N=3)。4.聚二烯丙基二甲基胺盐酸盐可以通过π-π键与石墨烯结合,组成阳离子聚电解质功能化的石墨烯。以硫堇为连接剂将纳米金附着在二氧化硅纳米小球上,纳米金不但为抗体提供了活性位点,而且起到信号放大作用。而硫堇既是连接剂,又是氧化还原的媒介体。将功能化的石墨烯修饰在电极表面,利用静电吸附作用将纳米金杂化的小硅球固定在电极上,再利用纳米金与抗体的吸附性有效的将抗体固定在修饰玻碳电极上。修饰电极的大的比表面积和它良好的生物相容性不仅增加了对抗体的固定量而且保持了抗体的生物活性。使得构建的免疫传感器具有较高的灵敏度,且该免疫传感器线性范围宽、重现性好、特异性高。更多还原

【Abstract】 Different methods have been used to improve the solvency of GR by functionalization or electrodeposition to prepare GR modified electrode. The main contents can be summarized as follows:1. The gold nanoparticles appear to adhere to GR that act as spacers to inhibit aggregation of GR sheets. The obtained GR/Au nanocomposites modified glassy carbon electrode exhibited high sensitivity in the detection of epinephrine (EP). It has been found that oxidation of EP at this modified electrode occurred at less positive potentials than on bare GCE. The anodic peak current observed were directly proportional to EP concentration between the range of5.0×10--8.0×10mol L-1(LOD=7.0×10-9mol L-1). At the same time, this electrode also showed favorable electrocatalytic activity toward some other small biomolecules (such as dopamine, β-nicotinamide adenine dinucleotide, uric acid et al.), suggesting the potential applications of GR/Au nanocomposites for constructing biosensors.2. A solution-based method was used to prepare GR/Au nanocomposites via a chemical co-reduction. The obtained GR/Au nanocomposites were easily dispersed homogeneously into N,N-dimethylformamide (DMF) in the presence of ionic liquids (ILs)1-butyl-3-methylimidazolium hexafluorophosphate ([BMIM][PF6]). First, GR/Au/ILs composites modified electrode (GR/Au/ILs/GCE) was fabricated. Second, thionine (Thi) was chemisorbed onto GR/Au/ILs films through the electrostatic force with the nano-Au. Then the result electrode was applied for the sensitive determination of hydrogen peroxide (H2O2). The results indicated that presence of ILs not only disperse the GR/Au nanocomposites but also increase the sensitivity for H2O2. The sensor displayed a linear range range from4.0×-6to2.9×10-3mol L-1. The detection limit was4.3×10-7mol L-1(S/N=3).3. A simple and rapid electrochemical method was developed for the determination of theophylline (TP), based on the excellent properties of ED-GO film. The result indicated that ED-GO film modified GCE exhibited efficiently electrocatalytic oxidation for TP with relatively high sensitivity and stability. The electrochemical behavior of TP at ED-GO/GCE was investigated in detail. Under the optimized conditions, the oxidation peak current was proportional to TP concentration in the range of8.0×10-7to6.0×10-5mol L-1with the detection limit of6.0×10-7mol L-1(S/N=3). The proposed method was successfully applied to green tea samples with satisfactory results.4. The fuctionalized graphene with poly(diallyldimethylammonium chloride)(PDDA-GR) was modifed on the glassy carbon electrode, which can increase the surface area to combine more negtive-charged prepared silica nanoparticles. Nano-gold was coated on silica nanoparticles through thionine linking, which was used to immobilize antibodies. Interlayer thionine was not only a bridging but also an excellent electron mediator. The proposed immunosensor exhibited simple fabrication, good reproducibility and a broad linear range.更多还原