Toward a better characterization of the aromatic and alicyclic components of marine dissolved organic matter: development and application of a one-step reduction reaction

更好地表征海洋溶解有机物的芳香族和脂环族成分：一步还原反应的开发和应用

• 批准号: 1155269
• 负责人: Lihini Aluwihare
• 金额: $ 28.93万
• 依托单位: University of California-San Diego Scripps Inst of Oceanography
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-02-15 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1155269&HistoricalAwards=false
• 关键词: Toward; better; characterization; aromatic; alicyclic

Identifying the chemical structure of compounds that constitute the refractory dissolved organic matter (RDOM) reservoir will yield new insights into the processes that control the accumulation and removal of organic matter from aquatic environments. A scientist from Scripps Institute of Oceanography will be working to optimize an existing chemical reduction technique to render oxidized aliphatic and aromatic dissolved organic matter (DOM), two compounds which together comprise as much as 60% of the carbon in RDOM, more amenable to gas chromatography (GC) separation. This will allow for the characterization of this important RDOM component. Much of the time and effort associated with the proposed research will be invested in identifying backbone structures of reduction products. To assist with this structural characterization, the proposal also seeks to adapt and modify existing GC×GC time of flight mass spectrometry techniques to better separate the complex mixture of reduction products. In addition to enabling more accurate compound characterization, this technique will also allow a more rapid determination of structural homogeneity within aquatic DOM. As part of this proposal, a preparatory GC×GC will also be modified such that methods developed using the previous instrument can be easily applied to isolate relevant compounds for further characterization (including isotope measurements). This work will also generate an MS library the aliphatic and aromatic reduction products that will be made available to other investigators interested in pursuing a similar avenue of research.Besides continuing to further develop the analytical method, the researcher also plans to apply the method to test three hypothesis, namely (1) that reduction will yield several aromatic compounds, some of which resemble degraded lignin; (2) that reduction will yield a range of alicyclic compounds including terpane derivatives; and (3) that GC×GC separation will confirm the presence of structurally related families of aromatic and aliphatic compounds. Samples for this study include Suwannee River fulvic acids and natural organic matter, ultrafiltered DOM isolated from the eastern tropical Pacific Ocean and western tropical Atlantic Ocean, DOM isolated from Circumpolar Deep Water in the Southern Ocean isolated using Agilent Bondesil PPL, and one surface and one deep water sample collected in the North Pacific subtropical gyre obtained using reverse osmosis/electrodialysis that will serve as an ad-hoc marine, reference DOM. Analyses of these four different DOM sample types will help to determine reaction and GC/MS-based analysis parameters to be optimized for each sample type and compound class under study. The analytical method to be developed and the mass spectrometry library for reduction products would be of interest to the science community. One graduate student would be supported and trained as part of this project. Two high school summer interns chosen with the help of the Ocean Discovery Center would also participate in the study. Students from this program tend to be underrepresented minorities.

识别构成难治性溶解有机物（RDOR）的化合物的化学结构，将对控制从水生环境中积累和去除有机物的过程产生新的见解。 Scripps海洋学研究所的一位科学家将致力于优化现有的化学还原技术，以使氧化的脂肪族和芳香族化有机物（DOM）构成两种化合物，两种化合物共同构成了RDOR中的60％的60％的化合物，更容易被气相色谱（GC）分离。这将允许表征这一重要的RDON组件。与拟议的研究相关的大部分时间和精力将投资用于识别还原产品的骨干结构。为了协助这种结构表征，该提案还试图适应和修改飞行质谱技术的现有GC×GC时间，以更好地分离还原产品的复杂混合物。除了实现更准确的复合表征外，该技术还将允许更快地确定水生dom内的结构均匀性。作为本提案的一部分，制剂GC×GC还将进行修改，以便可以轻松地将使用先前仪器开发的方法用于隔离相关化合物以进行进一步表征（包括同位素测量）。这项工作还将为MS图书馆生成脂肪型和芳香的还原产品，该产品将提供给有兴趣追求类似研究途径的其他调查人员。Besides继续进一步开发了分析方法，研究人员还计划应用该方法来测试三个假设，即（1）减少的芳族将产生几种芳族化合物，其中一些相关的脱脂蛋白； （2）减少将产生一系列的aliclic化合物，包括萜烷衍生物； （3）GC×GC分离将证实存在芳香和脂肪族化合物的结构相关家族。这项研究的样品包括Suwannee河富氏酸和天然有机物，从东部太平洋东部和西部热带大西洋中分离出的超过滤DOM，从南部的圆极深水中分离出来，使用安宁的粘合物PPL分离出来，并使用北部太平洋的水上散布的一台深水样品，一台深层的水样品，该水域在北太平洋的水上供应。临时海洋，参考DOM。对这四种不同的DOM样本类型的分析将有助于确定针对正在研究的每种样本类型和化合物类优化的反应和基于GC/MS的分析参数。科学界将要开发的分析方法和减少产品的质谱库。作为该项目的一部分，将为一名研究生提供支持和培训。在海洋发现中心的帮助下选择的两个高中暑期实习生也将参加这项研究。该计划的学生往往是人数不足的少数群体。