含铁、铜金属有机杂化材料在电分析检测色氨酸和亚硝酸根离子中的应用

发布时间：2019-01-10 07:16

【摘要】：金属有机骨架化合物(metal-organic frameworks,MOF)和金属有机凝胶(metal-organic gels,MOG)都是由金属离子与适当的有机配体通过配位键等化学作用结合形成的金属有机杂化材料。由于其具有大的比表面积、丰富的金属活性位点、优良的光学和电学特性,MOF和MOG在吸附、有机催化和化学传感等领域已有广泛应用。结合以上优良特性,本文侧重讨论含Fe的MOF和含Cu的MOG作为新型修饰电极材料,在电分析检测色氨酸和亚硝酸根离子方面的应用。具体的研究内容为:一、AgNPs/MIL-101(Fe)作为修饰电极材料对色氨酸的检测在含铁的MOF MIL-101(Fe)表面合成具有优良导电性能的银纳米颗粒,将该复合材料用作电催化剂修饰于电极表面,实现了对色氨酸(Trp)的灵敏检测。一方面,由于MOFs的高效吸附性能,可以吸附Trp在电极表面发生氧化反应;另一方面,AgNPs的优良导电性能能进一步提高电流响应。与裸电极(GCE)和MIL-101(Fe)/GCE修饰电极相比,AgNPs/MIL-101(Fe)/GCE修饰电极可以明显提高检测的电流信号。在最优条件下,检测Trp的线性范围为1 50μM和50 150μM,检测限为0.14μM。将所建立的方法用于尿样中Trp的加标检测,得到了较好的回收率。二、Cu-MOG的合成及其作为修饰电极材料对亚硝酸根离子的检测1.Cu-MOG的合成及表征以Cu~(2+)作为金属离子,2,6-双(2-苯并咪唑基)吡啶作为配体合成了绿色的含铜金属有机凝胶。考察了金属离子和配体的浓度、溶剂种类对凝胶形成的影响。X射线衍射、傅里叶红外等表征结果表明,在凝胶形成过程中,Cu~(2+)与咪唑基上的N配位,伴随着氢键、π-π堆积等弱作用力,形成了不透明的绿色凝胶。通过扫描电子显微镜观察发现,在对凝胶进行冷冻干燥处理去除溶剂后,其微观形貌得到了保留。2.MOG作为新型修饰电极材料对亚硝酸根离子的检测2,6-双(2-苯并咪唑基)吡啶配体含有的吡啶基团和亚胺N原子具有亲水性,因此,将制备好的金属有机凝胶进行冷冻干燥处理,得到了在水中分散性良好的金属-有机干凝胶。将其用做电催化剂修饰在电极表面,发现该修饰电极能够选择性识别亚硝酸根离子。与裸电极相比,修饰了MOG的电极能够提供更多的活性位点与靶物接触,从而产生更强的电流信号。在最优实验条件下,检测亚硝酸根离子的线性范围为2 150μM,检测限为0.86μM。我们将所建立的方法用于腊肠中亚硝酸根的加标检测,得到了较好的回收率。
[Abstract]:Organometallic matrix compounds (metal-organic frameworks,MOF) and organometallic gels (metal-organic gels,MOG) are organometallic hybrid materials which are formed by the combination of metal ions and appropriate organic ligands through coordination bonds and other chemical interactions. Because of its large specific surface area, abundant metal active sites, excellent optical and electrical properties, MOF and MOG have been widely used in adsorption, organic catalysis and chemical sensing. Combined with the above excellent properties, the application of MOF with Fe and MOG with Cu as new modified electrode materials for the detection of tryptophan and nitrite ions is discussed in this paper. The main contents are as follows: first, silver nanoparticles with excellent conductivity were synthesized on the surface of iron-containing MOF MIL-101 (Fe) by AgNPs/MIL-101 (Fe) as a modified electrode material for the detection of tryptophan. The composite was used as electrocatalyst to modify the electrode surface, and the sensitive detection of tryptophan (Trp) was achieved. On the one hand, Trp can be oxidized on the electrode surface due to the high efficiency of MOFs adsorption; on the other hand, the excellent conductivity of AgNPs can further improve the current response. Compared with bare electrode (GCE) and MIL-101 (Fe) / GCE modified electrode, AgNPs/MIL-101 (Fe) / GCE modified electrode can significantly improve the current signal. Under the optimal conditions, the linear range of Trp is 1 渭 M and 50 渭 M, and the detection limit is 0.14 渭 M. The established method has been applied to the determination of Trp in urine, and a good recovery rate has been obtained. Second, the synthesis of Cu-MOG and the determination of nitrite ion as modified electrode material; the synthesis and characterization of 1.Cu-MOG with Cu~ (2) as metal ion, Green copper-containing organo-gels were synthesized by using 2-6-bis (2-benzimidazolyl) pyridine as ligand. The effects of concentration of metal ions and ligands, kinds of solvents on gel formation were investigated. The results of X-ray diffraction and Fourier transform infrared spectroscopy showed that Cu~ (2) coordinated with N on imidazolyl group and accompanied by hydrogen bond during gel formation. 蟺-蟺 stacking and other weak forces formed an opaque green gel. By scanning electron microscope, it was found that after freeze-drying of gel, the solvent was removed. 2.MOG is a new modified electrode material for the determination of nitrite ion. The pyridine group and imine N atom contained in 2O6-bis (2-benzimidazolyl) pyridine ligands have hydrophilic properties. The metal-organic xerogels with good dispersion in water were obtained by freeze-drying the prepared organometallic gels. It was found that the modified electrode could selectively recognize nitrite ion. Compared with the bare electrode, the modified MOG electrode can provide more active sites to contact the target, thus producing a stronger current signal. Under the optimum experimental conditions, the linear range and detection limit of nitrite ion were 2 ~ 150 渭 m and 0.86 渭 m, respectively. The method has been applied to the standard determination of nitrite in sausages, and a good recovery rate has been obtained.
【学位授予单位】：西南大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O641.4;O657.1

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