多氯联苯论文：光谱分析技术在多氯联苯分析检测中的应用.doc

多氯联苯论文：光谱分析技术在多氯联苯分析检测中的应用【中文摘要】多氯联苯(polychlorinated biphenyls,PCBs)是一类持久性有机污染物。PCBs不仅具有致癌、致畸和致突变的毒性,还具有干扰内分泌的危害。因此PCBs对生态环境及人类健康有不可估量的潜在威胁。研究多氯联苯与光谱探针之间的相互作用,建立操作简便、高灵敏和低检出限的多氯联苯定量检测光谱分析新方法,对多氯联苯污染水平的预测、病理分析和临床诊断等方面具有重要的理论意义和应用价值,是目前国内外环境检测和分析化学研究的热点之一。本论文以荧光和共振光散射技术为主要研究手段,以寻找新型多氯联苯光谱探针,建立新的灵敏的PCBs定量测定方法为,并结合X-射线衍射(XRD)、高分辨透射电镜(HRTEM).圆二色光谱(CD)、紫外可见吸收光谱(UV-vis)等多种分析技术,探讨光谱探针与多氯联苯之间的相互作用机理。论文的主要内容如下：论文第一部分,综述了多氯联苯的特征和危害、处理技术及检测方法的研究进展。论文第二部分,利用共振光散射技术研究了纳米银和多氯联苯的相互作用。结果表明：多氯联苯可以显著增强纳米银的共振光散射强度,且体系共振光散射增强程度与多氯联苯的浓度在一定范围内具有良好线性关系,据此建立了定量测定多氯联苯的共振光散射检测新方法。2,4,4-三氯联苯(PCB28)、2,2,5,5-四氯联苯(PCB52)和3,3,4,4-四氯联苯(PCB77)的线性范围分别为：8.010-81.010.6 g mL-1,9.010.81.O10.6 g mL-1和4.010-81.010-6g mL-1,检出限分别为:2.610-8g mL-1,3.310-8g mL-1和6.310-9g mL-1.并将该方法用于合成样品中PCB77的测定,取得令人满意的结果。机理研究认为,多氯联苯吸附在纳米银的表面,形成了纳米银-多氯联苯聚集体,是该体系共振光散射强度增强的主要原因。论文第三部分,研究了盐酸小檗碱和多氯联苯的散射光增强作用。研究发现,多氯联苯可以使盐酸小檗碱的散射光强度产生增强作用,最大散射峰的波长位于396 nm,当PCBs摩尔数相同时,其增强程度为PCB77PCB52,这说明BER和PCBs之间存在相互作用,且相互作用强弱与PCBs结构有关。由此建立了-种以盐酸小檗碱作为散射光探针测定多氯联苯简便的新方法。在最佳实验条件下,多氯联苯浓度与散射光强度的增强程度之间具有良好的线性关系,PCB52和PCB77的线性范围分别为：1.010-74.010-6 mol L-1和6.810-81.510-6mol L-1,检出限分别为：3.010-8 mol L-1和1.510-8 mol L-1.论文第四部分,利用荧光光谱技术研究了牛血清白蛋白和多氯联苯的相互作用,建立了定量测定多氯联苯的荧光分析新方法。在最佳实验条件下,牛血清白蛋白多氯联苯体系荧光强度的增强程度与多氯联苯的浓度在一定范围内呈良好的线性关系,PCB52和PCB77的线性范围为：5.010-7-5.010-6mol L-1和8.910-81.510-6 mol L-1其检出限分别为：2.910-7mol L-1和2.610-8mol L-1。该方法具有选择性好,操作简单和灵敏度高等特点。机理研究表明：PCBs与BSA分子之间存在着相互作用,并导致BSA分子的二级结构发生变化。此外,PCB77与BSA分子芳环氨基酸残基发生了相互作用,其结合位点接近于BSA分子中酪氨酸残基。论文第五部分,研究表明多氯联苯与CdTe量子点之间存在着相互作用,导致了CdTe量子点的光散射增强,而荧光猝灭,且光散射增强与荧光猝灭之比与多氯联苯浓度在一定范围内呈线性关系,据此建立了测定多氯联苯的光散射荧光比率法。PCB52和PCB77的线性范围分别为：2.010-71.010-5 mol L-1和6.810-83.410-6 mol L-1,检出限分别为：1.510-7molL-1和2.110-8molL-1。本论文的主要特点：1、利用纳米银作为共振光散射探针来测定环境污染物多氯联苯,该方法具有灵敏度高,重现性好等优点,并探讨其相互作用机理。2、研究了多氯联苯对盐酸小檗碱的散射光强度增强效应,建立了简便的测定多氯联苯的新方法。3、基于多氯联苯对BSA的荧光增强效应,建立了可选择性测定PCB77的荧光分析新方法,机理研究表明PCB77与BSA分子芳环氨基酸残基发生了相互作用,其结合位点接近于BSA分子中酪氨酸残基。4、研究了CdTe量子点作为光谱探针,并利用灵敏度高、简便的光散射荧光比率法来测定痕量的多氯联苯,并用于合成样品中PCB77的测定。【英文摘要】Polychlorinated biphenyls (PCBs) are a kind of persistent organic pollutants (POPs). PCBs are not only carcinoenic, teratogenic and mutagenic, but also have the role of endocrine disruption. Thus, PCBs have an invaluable potential threat for ecological environment and human health. It is of significant value to study the interaction between spectral probes and PCBs, the quantitative analysis of PCBs with simple, high sensitivity and low detection limit are important in preliminary assessment of pollution levels, pathological analysis and clinical testing, which is helpful for the understanding of binding mode and reaction mechanism between persistent organic pollutants and spectral probes. Recently, the trace determination of PCBs has become a research hotspot of environmental science and analytical chemistry, which has attracted extensive attention.Based on the fluorescence and resonance light scattering (RLS) as the primary technique, this thesis focus on the development of new probes for polychlorinated biphenyls and to establish simple and sensitive methods for the quantitative determination of polychlorinated biphenyls with multiple techniques to study the interaction mechanism. The main conclusions are listed as follows:In the first section, we summarize the recent development of treatment technology and detection method for polychlorinated biphenyls.The progress of the characteristics and hazards of polychlorinated biphenyls is also commented.In the second section, the interaction between AgNPs and PCBs are stuied. From the research, we find that when PCBs are added to AgNPs solution, resonance light scattering of the system is significantly enhanced. Based on this, a novel resonance light scattering approach for the determination of PCBs is proposed. Under optimized conditions, there are linear relationships between the enhancing resonance light scattering intensity of the system and the concentrations of PCBs in the range of 8.010-81.010-6 g mL-1 for 2,4,4-trichlorbiphenyl (PCB28),9.010-81.010-6 g mL-1 for 2,2,5,5-tetrachlorbiphenyl (PCB52) and 4.010-81.010-6 g mL-1 for 3,3, 4,4-tetrachlorobiphenyl (PCB77). The corresponding detection limits (S/N=3) were 2.610-8 g mL-1 for PCB28,3.310-8gmL-1 for PCB52 and 6.310-9g mL-1 for PCB77, respectively. The interaction mechanism is considered that the enhancement of RLS of PCBs is ascribed to the formation of AgNPs-PCBs aggregate.In the third section, the scattered light enhancing effect of the system of berberine and PCBs is studied. After the addition of PCBs to the berberine solution, the scattered light intensity of berberine-PCBs system was obviously enhanced and reached a maximum at 396nm, which indicated that there existed interacions between berberine and PCBs. In addition, the extent of scattered light enhancement depends on the structrure of PCBs in the order PCB77 PCB52. Under optimum conditions, the enhanced scattered light intensity is proportional to the concentration of PCBs in the range of 1.010-7-4.010-6 mol L-1 for PCB52,6.810-81.510-6 mol L1 for PCB77. The detection limits (S/N=3) of PCB52 and PCB77 are 3.010-8 mol L-1 and 1.510-8 mol L-1, respectively.In the fourth section, we found that PCBs can enhance the fluorescence intensity of protein. Under optimum conditions, there are linear relationships between the enhancing fluorescence intensity of the system and the concentrations of PCBs in the range of 5.010-75.010-6 mol L-1 for PCB52,8.910-85.010-6 mol L-1 for PCB77. The corresponding detection limits (S/N=3) of PCB52 and PCB77 are 2.910-7 mol L-1, 2.610-8 mol L-1, respectively. Samples are satisfactorily determined. Furthermore, the fluorescence enhancement mechanism is discussed in detail. Results indicate that fluorescence enhancement of the system originates from the formation of BSA-PCBs complexes. In addition, PCBs are mainly bound to the tyrosine residues in BSA molecules.In the fifth section, it is found that PCBs have the interaction with CdTe quantum dots, resulting in strong enhanced light scattering and fiuorescecnce quenching of CdTe quantum dots. A new ratiometry of light scattering and fluorescence emission for the determination of PCBs using CdTe quantum dots as spectral probe is proposed. Under optimum conditions, the ratio vaule of light scattering intensity at 508 nm and fluorescence emission intensity at 558 is proportional to the concentration of PCBs in the range of 2.010-71.010-5 mol L-1 for PCB52,6.810-83.410-6 mol L-1 for PCB77. The detection limits (S/N=3) of PCB52 and PCB77 are 1.510-7mol L-1 and 2.110-8 mol L-1,respectively. This approach has been applied to the detection of PCB77 in synthetic sample with satisfactory results.The chief characteristics of this thesis are as follows:1. AgNPs is served as a resonance light scattering probe to determinate the trace of PCBs. This method has the advantages of high sensitivity, simple operation and good reproducibity. In addtion, the mechanism of the system is also discussed in detail.2. It is found that the resonance light scattering intensity of berberine-PCBs system is obviously enhanced after the addition of PCBs to the berberine solution.This method is simple, stable and quick.3. It is found that PCBs can enhance the fluorescence intensity of BSA molecules and provide a novel, selective and rapid fluorimetric approach for the determination of PCBs. The fluorescence enhancement mechanism is also discussed in detail.4. It is found that PCBs can significantly enhance light scattering and fluorescecnce quenching of CdTe quantum dots and provide a novel ratiometry of light scattering and fluorescence emission for the detection of PCBs. This met