Collaborative Research: Molecular Level Characterization of Organic Matter in Ice Cores using high-resolution FTICR mass spectrometry

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Grannas/0739691This award supports a project to fully develop the analytical protocols needed to exploit a relatively new technique for the analysis of soluble organic matter in ice core samples. The technique couples Electrospray ionization to high resolution Fourier transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS). Sample volume will be reduced and pre-concentration steps will be eliminated. Following method optimization a suite of ice core samples will be studied from several Antarctic and Greenland locations to address several hypothesis driven research questions. Preliminary results show that a vast record of relatively high molecular weight organic material exists in ice core samples and intriguing results from a few samples warrant further investigation. Several important questions related to developing a better understanding of the nature and paleo record of organic matter in ice cores will be addressed. These include developing a better understanding of the origin of nitrogen and sulfur isotopes in pre-industrial vs. modern samples, developing the methods to apply molecular biomarker techniques, routinely used by organic geochemists for sediment analyses, to the analysis of organic matter in ice cores, tracking the level of oxidation of homologous series of compounds and using them as a proxy for atmospheric oxidant levels in the past and determining whether or not high resolution FTICR mass spectral analysis can provide the ice core community with a robust method to analyze organic materials at the molecular level. The intellectual merit of this work is that this analytical method will provide a new understanding of the nature of organic matter in ice, possibly leading to the discovery of multitudes of molecular species indicative of global change processes whose abundances can be compared with other change proxies. The proposed studies are of an exploratory nature and potentially transformative for the field of ice core research and cryobiology. The broader impacts of these studies are that they should provide compelling evidence regarding organic matter sources, atmospheric processing and anthropogenic inputs to polar ice and how these have varied over time. The collaborative work proposed here will partner atmospheric chemistry/polar ice chemistry expertise with organic geochemistry expertise, resulting in significant contributions to both fields of study and significant advances in ice core analysis. Training of both graduate and undergraduate students will be a key component of the project and students will be involved in collaborative research using advanced analytical instrumentation, presentation of research results at national meetings, and will participate in manuscript preparation.