节点文献
环境中几种持久性有机污染物理化性质的分析研究
【作者】 彭瑜；
【导师】 杨小弟；
【作者基本信息】 南京师范大学 ， 分析化学， 2011， 硕士
【摘要】 持久性污染物是指具有持久性、半挥发性、生物累积性和高毒性等显著特性的天然和人工合成的有机污染物。随着化学工业和农业的发展,持久性有机污染物(POPs)在环境中因为其严重的危害性,成为了全球关注的焦点,越来越引起人们的重视。本文简单介绍了POPs的特点以及持久性有机污染物的环境行为,以及对其本身性质的分析和研究。主要内容如下：1.用简单而又优化的高效液相色谱(RP-HPLC)来预测多氯联苯类(PCBs)的正辛醇/水分配系数(Kow),本实验中所用的RP-HPLC法不同与其他文献,对于用HPLC测得的物质的保留时间用了类似于Huber的校正方法,也被称之为两点校正法,以此来建立有摇瓶法数据的12种型中性POPs的logKow与logkw的线性模型关系：logKow=(1.10±0.06)logkw-(0.28±0.22),其中R=0.986,F=398.8。实验测定他们在不同二元流动相比例下的保留时间,获得logk’和CB关系,再外推至纯水下的容量因子kw,通过以上实验得到的logkw-logkw的线性关系,可以准确地验证化合物p,p’-DDT、HCB、Hexamethylbenzene、PCB 28的Kow值,这些预测值与它们各自的摇瓶法数据值相差很小,从而来预钡PCB 118、PCB 138、PCB 180、PBDE15、PBDE 209的Kow值：5.99、6.10、6.62、5.32、7.97。从验证和预测的结果可以看出,本论文中采用两点校正法的HPLC法也是测得物质Kow值的一种有效和可靠的实验方法。2.紫外光谱、荧光光谱方法研究了有机氯农药p, p’-DDD、p, p’-DDE, p,p’-DDT这3种农药分子与NADH间的相互作用。本文的研究结果发现：1)紫外和荧光的实验结果都表明有机氯小分子(DDD、DDE、DDT)都能与NADH发生作用,2)pH=6.5时DDD、DDE易与NADH相结合,并影响到相连的腺嘌呤环和二氢尼克酰胺环上的电子分布；3)在pH= 6.5 Tris-HCl缓冲溶液中DDT的存在使辅酶二氢尼克酰胺环的结构发生了的改变。这几种农药污染物可能都是以一种模式与NADH作用且最可能的作用模式为嵌插结合。此实验结果有助于深入理解环境生物体系中有机氯小分子的致毒机制和脱毒机理。
【Abstract】 Persistent organic pollutants (POPs) refer to the persistent, semi-volatile, bioaccumulative and highly toxic, and other notable features of natural and synthetic organic contaminants. With the development of chemical industry and agriculture, because of their serious harms, POPs in the environment have drawn increasing attention globally. This paper briefly describes the characteristics of POPs and environmental behavior, as well as the nature of its own analysis and research. The major contents are as follows:1. An improved retention time correction method, dual-point retention time correction (DP-RTC) is proposed for reversed-phase high performance liquid chromatography (RP-HPLC), which is used as a commonly indirect experimental measurement for determining n-octanol/water partition coefficient (Kow) value. To obtain reliable Kow data, a semi-empirical logKow-logkw regression logKow= (1.10±0.06) logKw-(0.28±0.22) with an R2cv= 0.972, R=0.986 is established by plotting a set of reliable directly experimental Kow values against the corresponding corrected retention time of 12 benzene homologues, which are chosen as model compounds in this study. This estimation method is further validated by four verification compounds, HCB, Hexamethylbenzene, p,p’-DDT, and PCB 28, whose logKow values are both determined by DP-RTC-improved RP-HPLC method and theoretical calculation methods and are compared with reported slow-stirring measured ones respectively, and values determined by the former method are found to give better consistency with slow-stirring measurement, even for highly hydrophobic environmental contaminants (logKow > 6). Finally, this logKow - logKw model are applied for predicting physico-chemical parameter Kow for PCB 118, PCB 138, PCB 180, PBDE 15 and PBDE 209, and the estimated logKow values for these five persistent organic pollutants (POPs) are 5.99,6.10,6.62,5.32, and 7.97, respectively.2. UV spectra, fluorescence spectroscopy spectroscopy study of organochlorine pesticides p, p’-DDD, p, p’-DDE, p, p’-DDT pesticides in these three kinds of interaction between molecules and NADH. This study found that:1) UV and fluorescence experiments have shown that small molecules of organic chlorine (DDD, DDE, DDT) and NADH can play a role,2) pH=6.5 when the DDD, DDE and easy combination with NADH and impact associated nicotinamide adenine ring and the dihydro ring electronic distribution; 3) pH=6.5 Tris-HCl buffer solution the presence of DDT-dihydro-coenzyme nicotinamide ring structure has changed. These types of pesticide contamination may have been in a role model and NADH, and the most likely mode of action for the intercalative binding. These results help us to understand biological systems, environment, small molecules of organic chlorine toxic mechanism and detoxification mechanism.