New Solid-State NMR Techniques for Analyzing Insoluble Organic Matter

用于分析不溶性有机物的新型固态核磁共振技术

• 批准号: 0138117
• 负责人: Klaus Schmidt-Rohr
• 金额: $ 28.14万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2006-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0138117&HistoricalAwards=false
• 关键词: New; Solid; State; NMR; Techniques

In this project supported by the Analytical and Surface Chemistry and the Geology and Paleontology Programs, Professor Klaus Schmidt-Rohr and coworkers at Iowa State University, advanced solid-state NMR methodologies will be developed and applied to identify at least 40 specific functional groups and estimate their concentrations in natural organic matter. This will be achieved by means of a set of efficient new spectral-editing pulse sequences based on heteronuclear dipolar couplings or chemical-shift anisotropies. Furthermore, the larger environment of a given functional group will be identified in two- and three-dimensional correlation experiments, and inhomogeneities on a 1- to 50-nm scale by spin diffusion. NMR dynamics measurements will enable the search for soft mobile regions that have been invoked to explain the partitioning of organic contaminants into soil organic matter. Near the end of the project, improved structural models for examples of soil and marine organic matter will be generated. Nuclear magnetic resonance spectroscopy will be used to elucidate the chemical and supramolecular structures of insoluble organic substances that are presented by the natural environment, such as soil and marine organic matter, kerogen, or bituminous materials. To this end, advanced solid-state nuclear magnetic resonance methods are being developed that can identify and quantify a large number of chemical groups in organic solids. In addition, nanometer-scale domains will be characterized. The NMR methods will be used to characterize the chemical binding sites of contaminants; to help understand nutrient release into soil; to indicate methods for enhanced carbon sequestration in soil to reduce "greenhouse gases" in the atmosphere; and to shed light on the chemical processes of soil, kerogen, and fossil-fuel formation. This will help to provide deeper insights into the chemical history of natural organic matter, its role in the global carbon cycle, and the results of human activities on the environment.

在这个项目中，由爱荷华州立大学的 Klaus Schmidt-Rohr 教授及其同事支持的分析和表面化学以及地质和古生物学项目，将开发和应用先进的固态 NMR 方法来识别至少 40 个特定的官能团并估计它们在天然有机物中的浓度。这将通过一组基于异核偶极耦合或化学位移各向异性的高效新光谱编辑脉冲序列来实现。 此外，将在二维和三维相关实验中识别给定官能团的更大环境，并通过自旋扩散识别 1 至 50 nm 尺度的不均匀性。核磁共振动力学测量将能够搜索软移动区域，这些区域已被用来解释有机污染物向土壤有机质的分配。项目临近结束时，将生成土壤和海洋有机物示例的改进结构模型。核磁共振波谱将用于阐明自然环境中存在的不溶性有机物质的化学和超分子结构，例如土壤和海洋有机物、干酪根或沥青材料。为此，正在开发先进的固态核磁共振方法，可以识别和量化有机固体中的大量化学基团。 此外，还将对纳米级域进行表征。 核磁共振方法将用于表征污染物的化学结合位点；帮助了解养分释放到土壤中的情况；指出加强土壤固碳以减少大气中“温室气体”的方法；并揭示土壤、干酪根和化石燃料形成的化学过程。这将有助于更深入地了解天然有机物的化学历史、其在全球碳循环中的作用以及人类活动对环境的影响。