RUI: Analytical Method Development for MSn Characterization of Humic Substances

在地球科学部水文科学项目的共同资助下，分析和表面化学项目支持南阿拉巴马大学的Alexandra Stenson教授研究微制备色谱的发展和使用，以及超高分辨率多维质谱分析，以阐明对环境具有重要意义的腐植质物质的结构组成。腐殖质分子表征最直接的障碍是这些样品的巨大复杂性。傅里叶变换-离子回旋共振质谱（FT-ICR MS）已被证明可以分辨单个腐殖质离子，并提供分子水平上的信息（例如分子式）。更详细的结构（相对于仅仅是成分）数据将需要对单个离子进行多维质谱实验，这种方法目前受到样品复杂性的阻碍。因此，本研究的第一个目标是通过定制的“微制备”色谱来降低样品的复杂性。金属络合和细胞内反应被用来获得进一步的官能团信息。目前，对于诸如固体和液体废物管理（包括放射性废物）以及金属、碳和营养循环的精确详细描述等重要的环境考虑而言，缺乏关于腐殖质物质的结构信息是一个问题。这项工作有望为完整的结构表征奠定基础，一旦实现，将转变为大量的环境重要领域。本科生完全参与工作，提供了非凡的研究机会。

With co-funding from the Hydrolgic Sciences Program in the Division of Earth Sciences, the Analytical and Surface Chemistry Program supports Prof. Alexandra Stenson of the University of South Alabama to investigate development and use of micro-preparative chromatography followed by ultra-high resolution multi-dimensional mass spectrometry for elucidating the structural composition of humic substances of environmental importance. The most immediate stumbling block to molecular characterization of humic substances is the immense complexity of such samples. Fourier Transform-Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS) has been demonstrated to resolve individual humic ions and to provide information on the molecular level (e.g. molecular formulae). More detailed structural (vs. merely compositional) data will require multidimensional MS experiments on individual ions, an approach that is currently hindered by sample complexity. Thus, the first goal of this research is to reduce sample complexity through tailored "micro-preparative" chromatography. Metal-complexation and in-cell reactions are employed to garner further functional group information. The lack of structural information on humic substances is presently an issue for such important environmental considerations as solid and liquid waste-management (including radioactive waste), as well as the precise detailing of metal-, carbon-, and nutrient-cycles. This work promises to lay the groundwork for complete structural characterization, which, once achieved, would be transforming to a plethora of environmentally important fields. Undergraduates are thoroughly involved in the work, providing extraordinary research opportunities.