RUI: Analytical Method Development for MSn Characterization of Humic Substances

University Of South Alabama, Mobile AL

Investigators

Abstract

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.