【作者】 王庚；

【导师】 杨国生；

【作者基本信息】 山东大学 ， 分析化学， 2008， 硕士

【摘要】 砷、汞、镉、铅等有毒重金属元素超标一直是危害人类健康的严重问题。砷、汞、镉、铅等的化合物进入人体后积蓄且不易排出体外,对人类造血系统、免疫系统、神经系统、生殖系统等多方面器官造成严重损害。同时,环境科学与生命科学中的元素行为效应并不仅仅取决于该元素的总量,特定的元素只有在特定的浓度范围和一定的存在形态下才能对生命系统和生物体产生有害作用。例如:甲基汞比无机汞的毒性更大,有机锡有毒性,而无机锡没有;形态越复杂的有机砷,毒性越弱,而无机砷的毒性则很大。因此,鉴别并能准确测定海产品及环境中元素的化学形态对评价有毒重金属元素对人体的危害,具有更重要的意义。电感耦合等离子体质谱(ICP-MS)是20世纪80年代发展起来的具有灵敏度高、精密度好、检出限低、多元素同时检测的分析特性,被广泛用于不同类型样品中痕量元素的分析研究。本文利用ICPMS以及HPLC-ICP-MS联用技术对海洋沉积物、海产品和中药材中的重金属元素及汞砷形态进行了分析。现将本文主要研究成果总结如下:1.比较了王水回流、微波消解、密闭容器消解三种不同方法消解沉积物样品的效果,结果表明消解效果有较大差异:王水回流不能将样品消解完全,而密闭容器消解和微波消解基本能将样品消解完全,但微波消解效果更好。建立了ICP-MS法同时测定12种重金属元素的分析方法,并用于南黄海16个站位点沉积物样品的重金属含量测定,发现不同重金属分布具有一定的区域性特点。该方法首次用于我国南黄海倾废专项调查,其结果可为海洋污染源的确认提供科学信息。2.海洋环境(如海洋沉积物、海产品等)中特定污染元素如汞在环境中具有蓄积和生物可利用性,其毒性和生物蓄积作用很大程度上依赖于其存在的化学形态,虽然在环境和生物样品中汞的形态不很复杂,但由于样品基体的复杂性及汞化合物的毒性,使得汞的形态分析越来越受到人们的重视,也受到科研工作者越来越多的关注。本论文利用3种不同的汞化学形态提取方法,并结合HPLC的高效分离选择性,建立了HPLC-ICP-MS联用技术对三种汞形态(甲基汞、无机汞、乙基汞)的分析方法,8 min内能实现三种汞化学形态的快速分离检测,并成功用于南黄海沉积物样品中汞化学形态的分析,结果令人满意。为了解汞在海洋系统的迁移转化、毒性及可能产生的环境危害提供了一种有价值的分析技术。3.建立了微波消解-ICP-MS同时测定海产品中砷、镉、汞、铅四种有害重金属元素的分析方法,其各元素相关系数均在0.9999以上,检出限分别为11.3μg/L、0.2μg/L、0.8μg/L、0.2μg╱L,能满足海产品中有毒有害重金属元素的分析要求。利用该法对南黄海7个及其他海域29个海产品的重金属元素进行了分析测定,发现有多个样品出现不同程度的超标问题,个别海产品,如花螺中砷含量高达45.62mg/kg。进一步比较了酸碱两种方法对海产品中汞形态的提取效率,在第二章所建汞化学形态分析方法基础上,用HPLC-ICP-MS联用技术分析测定了海产品中的汞化学形态。研究结果表明海产品存在的汞化学形态以毒性很大的甲基汞为主,虾(HH09)和虾(HH02)的MeHg/HgT分别高达83.5%和94.2%。此法可为我国海产品中有毒有害重金属元素汞的限量规范修改及海产品安全控制提供了一个科学评价方法,具有重要意义。4.中药材中微量元素的形态分析是当代医药研究和生命科学中的一重要课题。进行中药材中元素砷所存在化学形态的分析可为其毒理研究及安全评价提供一定的科学依据。中药材成分复杂,分析难度较高,本章利用微波消解/ICP-MS测定了24种中药材中的铜砷镉汞铅等5种有害重金属元素含量,结果表明中药材中有害重金属元素含量超标问题严重,必须在生产过程中予以重视。另外,建立了HPLC-ICP-MS联用技术对6种不同形态的砷化合物(As(Ⅲ)、As(Ⅴ)、DMA、MMA、AsB和AsC)的分析方法,并用于6种中药材样品中砷化学形态的分析。实验发现中药材中砷存在的主要化学形态是无机砷形态As(Ⅴ)、As(Ⅲ),而动物药材中还存在微量的AsB。此法主要优点在于简便快速、测定灵敏度高、检测限低、线性范围宽等,适于中药材质量控制、中药材的药理和毒理研究,以及更清楚地解释中药材中砷的作用机理。更多还原

【Abstract】 The contamination of toxic metals in the environment and biological matrices (seafood) is becoming a serious problem endangering human health. Heavy metals such as mercury, arsenic, lead, cadmium, etc, upon human uptake, are known to bio-accumulate in the body, causing severe damage on the blood, immunity, nerve and reproductive systems. Simultaneously, the determination of merely the total amount of the heavy metals in a sample is not sufficient for safety risk assessment. Elemental speciation is of vital importance because the toxicity of the hazardous element depends not only on the quantity involved, but more importantly, also the chemical forms of the element. For instance, the toxicity of methylmercury and organotin is higher than the inorganic mercury and tin, respectively. Inorganic arsenic compounds are highly toxic, while the organic forms of arsenic carry low toxicity. On the other hand, both arsenobetaine and arsenosugars are considered non-toxic. Against this background, the development of techniques for the effective determination of heavy metals and speciation in environmental and biological matrices is an area which has been attracting increasing attention in recent years.Since the introduction in 1980, inductively coupled plasma mass spectrometry (ICP-MS) has developed into an accurate and sensitive technique for multi-element determinations in a range of sample matrices. Compared with FAAS. GFAAS and ICP-OES, ICP-MS offers better sensitivity and excellent accuracy with multi-element, and has been used for all kinds of complicated samples. In this paper, These methods involving ICP-MS and HPLC-ICP-MS have been used for the determination of heavy metals and mercury species in some marine samples, and arsenic species in Chinese medicinal herbs.Main results obtained in this study can be summarized as follows:1. Certified reference material was treated with royal water circumfluence digestion, sealing vessel digestion and microwave digestion. The result of digestion was compared. The royal water circumfluence could not digest all the samples. Moreover, the latter methods completely digested marine samples. In addition, a method involving inductively coupled plasma-mass spectrometric analysis has been established and used for the determination of 12 kinds of heavy elements in marine sediments. Sediment samples collected from different positions were found to give distinct distribution patterns of trace elements. The method is first used for the investigation of the South Yellow Sea. The results provide the information about marine contaminative source.2. Toxicity and bioavailability of mercury species is highly dependent on its chemical structure. Methylmercury is the most toxic form of mercury which is particularly susceptible to bio-magnification in aquatic food webs. The accumulation of methylmercury in aquatic systems continues to pose a threat to fish and other biota including man. Speciation analysis of mercury in environmental and seafood samples has been a subject of great concern all the time. Speciation analysis of mercury is, therefore, mandatory in environmental studies. In this paper, three simple and rapid extraction methods are developed for the extraction of mercury species in sediment samples. A method employing HPLC-ICP-MS analysis has been developed for speciation analysis of inorganic mercury and organic mercury in extracts from marine sediments. The proposed method has been used for the speciation analysis of mercury in marine sediments from the South Yellow Sea. The proposed method provides an analytical approach for the understanding of migration and transformation, toxicity and the potential damage to environment of the mercury in ocean system.3. The method involving Microwave digestion and ICP-MS analysis has been established and used for the determination of four hazardous elements (As,Cd,Hg,Pb) in 36 kinds of seafood samples. The method has been validated using certified reference materials (DORM-2), assessing its quality in terms of accuracy, repeatability and detection limit. The results obtained show the validity of the proposed method to analyze real samples. Good linearity of the calibration is obtained for all target elements(r>0.9999). Detection limits for these four elements are 0.2μg/L(Cd,Pb), 0.8μg/L(Hg) and 11.3μg/L(As). These results show that the problem of hazardous elements in seafood was very serious, such as the amount of arsenic in whelk is very great and about 45.62 mg/kg.The HPLC-ICP-MS method has been combined with two extraction methodologies using alkaline digestion and acid digestion for extraction and quantitative analysis of inorganic mercury and organic mercury simultaneously in biota samples. The analytical results indicate that methyhnercury was the main chemical species in seafood samples. The percentages of MeHg in HgT were 83.5% to 94.2% in two shrimp samples from different sampling positions. The high performance of the methodology can be applied for the quality control and safety evaluation of the mercury speciation analysis in seafood. 4. In Chinese medicinal herbs, the trace element analysis is a hot topic in contemporary medicine and life sciences research. The speciation analysis of arsenic in Chinese medicinal herbs provides certain scientific basis for its toxicology research and safety evaluation. The Chinese medicinal herbs has complicated composition, and be therefore difficult to analysis. In this chapter, the method involving microwave digestion and ICP-MS analysis has been used for the determination of five hazardous elements (Cu,As,Cd,Hg,Pb) in Chinese medicinal herbs. These results indicate that the problem of poisonous element in Chinese medicinal herbs samples was very serious, more attention should be paid to this problem in the production of Chinese medicinal herbs.In addition, the development of the hyphenated technique of HPLC-ICP-MS method has been established for the separation and simultaneous determination of arsenobetaine (AsB), arsenocholine (AsC), arsenite (AsIII), arsenate (AsV), monomethylarsonic acid (MMA) and dimethylarsinic acid (DMA). And the method was proposed for the speciation analysis of arsenic in 6 kinds of Chinese medicinal herbs. From this work, it was found that As (Ⅴ), As (Ⅲ) were the main chemical species in Chinese medicinal herbs, however, a little AsB in animal herbs. As for the merits of high sensitivity, effective separation and low detection limits, this feasible method can be applied for quality control of five hazard elements and arsenic speciation analysis in Chinese medicinal herbs. The information should be of value to scientists involved in the pharmacological research of realgar and cinnabar in Chinese medicinal herbs.更多还原