RCEES OpenIR  > 环境化学与生态毒理学国家重点实验室
识别新型环境污染物的高分辨质谱分析方法研究
Alternative TitleStudy on High Resolution Mass Spectrometer-based Analytical Methods for Screening of Emerging Environmental Contaminants
林泳峰
Subtype博士
Thesis Advisor江桂斌 ; 阮挺
2019-06
Degree Grantor中国科学院生态环境研究中心
Place of Conferral北京
Degree Name理学博士
Degree Discipline分析化学
Keyword新型有机污染物、全氟/多氟烷基化合物、Toxcast化合物、高分辨质谱、疑似靶标/非靶标分析方法 emerging Contaminants, Per- And Polyfluoroalkyl Substances, Toxcast Chemicals, High Resolution Mass Spectrometer, Suspect/nontarget Screening
Abstract

      伴随着化学技术和化工工业的快速发展,全球每年有成千上万的化合物被合成并应用于工业生产和日常生活中。在大量生产和使用过程中,越来越多的化合物被排放到环境中成为新型污染物,对环境和人体健康造成了潜在风险。我们课题组在2006年提出从环境中发现新型污染物的研究方向,通过建立系列的筛选与识别技术,在环境中发现了几十种具有重要环境意义的新型污染物。目前,如何在环境中发现新型污染物已经成为国际环境科学领域研究的热点问题。
      高分辨质谱(high resolution mass spectrometer, HRMS)在化合物的结构解析中具有独特优势,可克服缺乏化合物标准品的难题,同时可进行数据的回溯性分析和污染物的高通量筛选,因此在新型有机污染物的筛选和识别中有广阔的应用前景。本论文基于液相色谱—高分辨质谱仪器,建立了筛选和识别环境中新型有机污染物的目标、疑似靶标和非靶标分析流程,发现了环境中的氯代多氟和氢代多氟醚基磺酸类化合物、毒性效应(ToxCast)化合物在污泥、大气细颗粒物等复杂环境介质中的赋存状态和浓度分布。
      全氟/多氟烷基化合物(per- and polyfluoroalkyl substances, PFASs)是一类重要的人工合成化学品,在各行各业都有广泛的应用。随着传统PFASs如全氟辛基磺酸(perfluorooctane sulfonic acid, PFOS)的限制使用,多种具有不同结构分子的新型PFASs被合成作为替代品应用于工业生产和日常生活中。针对环境水体中的全氟磺酸(perfluoroalkane sulfonic acids, PFSAs)、氟调聚磺酸(fluorotelomer sulfonic acids, FTSAs)和6:2氯代多氟醚基磺酸(6:2 chlorinated polyfluoroalkyl ether sulfonic acids, Cl-6:2 PFESA)3类新型PFASs,优化了其固相萃取前处理过程,并开发了超高效液相色谱Orbitrap高分辨质谱联用(UPLC-Orbitrap HRMS)的仪器分析方法。与常用的液相色谱三重四级杆质谱联用(LC-QqQ MS)分析方法相比,UPLC-Orbitrap HRMS分析方法同样可实现目标PFASs的同步定性和定量分析。该方法具有优异的方法学参数,方法检出限为7.1 – 62 pg/L,线性相关系数(R2)> 0.9990。对河水样本中目标PFASs的定量结果与LC-QqQ MS方法的定量结果具有高度一致性。将开发的UPLC-Orbitrap HRMS分析方法用于环境介质中新型Cl-PFESAs污染物类似物的疑似靶标分析。在来自我国不同地区的污泥样本中发现了3个Cl-PFESAs同系物:Cl-6:2 PFESA、Cl-8:2 PFESA和Cl-10:2 PFESA。定量分析结果发现,Cl-PFESAs在我国有广阔的地域分布,Cl-6:2 PFESA、Cl-8:2 PFESA和Cl-10:2 PFESA的检出率分别为100%、89.3%、23.2%,残留浓度水平分别为0.02 – 209 ng/g、n.d. – 31.8 ng/g、n.d. – 0.86 ng/g(干重)。其中Cl-6:2 PFESA为最主要的Cl-PFESAs污染物,几何平均浓度为2.15 ng/g,在部分地区污泥样本中其浓度已超过PFOS成为主要的PFAS污染物。
      深入探讨了Cl-6:2 PFESA的可降解能力,实验发现Cl-6:2 PFESA在体外超还原态氰钴胺厌氧体系中发生快速降解。建立了基于UPLC-Orbitrap HRMS的非靶标分析流程,筛选并识别出3个脱卤加氢还原转化产物:1H-6:2 PFESA、2H-6:2 PFESA和1H-6:2 PFUESA。1H-6:2 PFESA为主要的转化产物,产率达到87.7%。为了进一步确认Cl-6:2 PFESA是否可在自然环境中发生降解,采集了Cl-6:2 PFESA的主要使用企业——两个电镀工业园区——周边河流的河水和底泥样本。首次在环境中发现了一类新型有机污染物H-PFESAs,包括1H-6:2 PFESA和1H-8:2 PFESA。1H-6:2 PFESA在河水和底泥样本中的几何平均浓度分别为560 pg/L、11.1 pg/g;1H-8:2 PFESA在在河水和底泥样本中的几何平均浓度相对较低,分别为11.0 pg/L、7.69 pg/g。在检测的18个PFASs中,1H-6:2 PFESA和1H-8:2 PFESA总浓度的占比在两个采样区域分别为1%和0.1%。
      细颗粒物(PM2.5)污染造成的对生态环境和人体健康的不利影响已经引起广泛关注。目前的若干研究针对常见的持久性有机污染物及其气固分配行为,对其中存在的新型有机污染物的种类和数量认识不足。毒性预测(ToxCast)项目是由美国环保署提出,通过离体试验和毒性预测手段对有机化合物的毒性进行评估,旨在高通量筛选可能对环境和人体健康产生负面影响的需要优先考虑的化合物。ToxCast第一期和第二期从多个重要的化学品目录清单中选取的化学品涵盖了不同的官能团结构和化合物用途,同时作为阳性对照化合物,具有显著的生物活性位点。因此,这些化学品在环境中的赋存和行为特征对于评价细颗粒物有机污染物的赋存规律和暴露风险具有重要意义。基于以上思考,根据ToxCast第一期和第二期化学品建立了内部数据库,共包含890个ToxCast化合物。采用UPLC-Orbitrap HRMS分析方法,建立了疑似靶标筛选流程,在北京市2016年采集的PM2.5样本中识别出12类具有不同官能团结构的共89个ToxCast化合物。定量结果显示,邻苯二甲酸酯、苯酚和羧酸酯化合物浓度水平较高,平均浓度分别为7.82 ng/m3、4.42 ng/m3和4.11 ng/m3。化合物浓度水平(或仪器响应)随时间变化呈现4种不同的变化规律,与气象因素(日均温度、PM2.5浓度)的变化具有显著相关性。对环境中常见的大气有机污染物进行回溯性分析,识别出75个化合物。

Other Abstract

      Thousands of synthetic chemicals are produced worldwide annually, and their emission into the environment is inevitable during production and application processes. The presence and environmental behaviors of emerging contaminants have aroused increasing concern due to their potential risks to the environment and human health. Our research group has focused on the occurrence of emerging contaminants since 2006, and dozens of novel pollutants with crucial environmental significance have been identified by a series of chemical structure screening and elucidation approaches. Nowadays, it has become a hot spot issue in environmental sciences.
      Extensive efforts have been carried out to tackle this environmental issue. Analytical strategies based on high resolution mass spectrometer (HRMS) have been proved effective considering its superiority in chemical structure identification. The dilemma of chemical standards lacking could be conquered, further data mining and retrospective analysis could also be achieved. In this study, HRMS-based analytical methods including target, suspect and nontarget screening workflow were established to identify the emerging contaminants in various environmental matrices. Presence of novel chlorinated and hydrogen-substituted polyfluoroalkyl ether sulfonic acids (Cl-PFESAs and H-PFESAs), and ToxCast chemicals was confirmed in the environment. Further environmental behaviors and fates of these emerging contaminants were also investigated.
      Per- and polyfluoroalkyl substances (PFASs) are a group of widely used synthetic chemicals, which are ubiquitously detected in various environmental compartments and biological species. Due to restrictions on production and usage of conventional PFASs such as perfluorooctane sulfonic acid (PFOS), numerous novel PFASs with distinct functional groups emerge as alternatives. An analytical method was developed in this study to analyze several emerging PFASs in river water samples, including perfluoroalkane sulfonic acids (PFSAs), fluorotelomer sulfonic acids (FTSAs) and 6:2 chlorinated polyfluoroalkyl ether sulfonic acid (Cl-6:2 PFESA). Solid phase extraction procedure was optimized, and an instrumental method using ultra-high performance liquid chromatograph coupled with Orbitrap HRMS (UPLC-Orbitrap HRMS) was developed. Results showed that the simultaneous qualitative and quantitative analysis of target analytes could be achieved by the developed UPLC-Orbitrap HRMS method, with method detection limits in a range of 7.1 – 62 pg/L and linearity (R2) > 0.9990. Moreover, the quantified analyte concentrations in river water samples obtained by the UPLC-Orbitrap HRMS method were quite coincident with results acquired by UPLC coupled with triple quadrupole MS (UPLC-QqQ MS) method, demonstrating feasibility of the developed UPLC-Orbitrap HRMS method for qualitative and quantitative analysis of emerging PFASs.
      The developed UPLC-Orbitrap HRMS method were applied for the occurrence of the novel Cl-PFESA analogues in sewage sludge samples by a suspect screening strategy. Three Cl-PFESA homologues were identified in sludge samples from different regions of China, including Cl-6:2 PFESA, Cl-8:2 PFESA and Cl-10:2 PFESA. Widespread of Cl-PFESA contaminants were monitored, the concentrations of Cl-6:2 PFESA, Cl-8:2 PFESA and Cl-10:2 PFESA in sludge samples were 0.02 – 209 ng/g, n.d. – 31.8 ng/g and n.d. – 0.86 ng/g (dry weight), respectively. Cl-6:2 PFESA was the most predominant analogue with geomean concentration of 2.15 ng/g.
The susceptibility of Cl-6:2 PFESA to reductive dehalogenation was further tested in an anaerobic super-reduced cyanocobalamin assay, and rapid transformation of dosed Cl-6:2 PFESA was observed. An integrated nontarget screening workflow was established to discern its transformation products, with three major products identified (1H-6:2 PFESA, 2H-6:2 PFESA and 1H-6:2 PFUESA). 1H-6:2 PFESA was the dominating transformation product with a yield of 87.7%. River water and sediment samples collected from two separate regions with metal-plating activities were further analyzed. Presence of 1H-6:2 PFESA and 1H-8:2 PFESA was detected, whose geomean concentrations were 560 pg/L and 11.0 pg/L in river water samples, and 11.1 pg/g and 7.69 pg/g in sediment samples, respectively. The total concentrations of 1H-6:2 PFESA and 1H-8:2 PFESA contributed to 1% and 0.1% of the 18 monitored PFAS pollutants in the two separate sampling regions, respectively.
      Airborne fine particulate matter (PM2.5) has been raised increasing attention due to its adverse effects to the environment and human health. Current studies mainly focused on the conventional persistent organic pollutants and their gas-particle phase partitioning behaviors. However, huge knowledge gaps still exist on the categories and numbers of emerging contaminants in PM2.5. Toxicity Forecaster (ToxCast) program is a project launched by the United States Environmental Protection Agency, which aims to rank and prioritize chemicals by high throughput screening in vitro assays and computational toxicology approaches. The selected chemicals in ToxCast Phase I and Phase II cover numerous emerging contaminants with various functional groups and applications from multiple chemical inventories of interest. Meanwhile, they are used as positive controls for monitoring diverse active biological processes. Therefore, the occurrence of these compounds in PM2.5 is of great importance for further risk assessment. An in-house database containing 890 unique ToxCast (Phase I and Phase II) chemicals was constructed, and presence of these chemicals in sixty PM2.5 samples from January to December of 2016 in Beijing was confirmed by a suspect screening workflow. Finally, 89 compounds were identified in 12 substance categories, which covered a broad range of physico-chemical properties. Quantification/semi-quantification results showed that phthalates, phenols and carboxylic esters were the three most predominant substance categories, with mean concentrations of 7.82, 4.42, 4.11 ng/m3, respectively. Four diverse temporal variation patterns were discerned, which could be explained by correlations of chemical concentrations (or instrumental responses) with meteorological parameters (daily temperature and PM2.5 concentration). An extended retrospective suspect analysis was further performed to reveal the presence of several frequently monitored contaminants in atmospheric environment, with another 75 pollutants tentatively identified. 

Pages204
Language中文
Document Type学位论文
Identifierhttp://ir.rcees.ac.cn/handle/311016/42246
Collection环境化学与生态毒理学国家重点实验室
Recommended Citation
GB/T 7714
林泳峰. 识别新型环境污染物的高分辨质谱分析方法研究[D]. 北京. 中国科学院生态环境研究中心,2019.
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