Research Interest

My research group focuses on the application of advanced analytical techniques, including ultrahigh resolution mass spectrometry, solid state 13C NMR spectroscopy and 3-D excitation-emission fluorescence spectroscopy, in studies of the organic chemistry of natural waters and sedi¬ments. We are particularly interested in the composition, structure and biogeochemical reactivity of dissolved natural organic matter (DOM), including DOM containing nitrogen and phosphorus. In 1997, in collaboration with co-workers at the National High Magnetic Field Laboratory, we published the first description of the use of electrospray ionization and high-field FT-ICR mass spectrometry do characterize humic and fulvic acids, and we have been developing and refining this technique since that first paper appeared. The rapid evolution of FT-ICR MS for applications in the geosciences can be appreciated by comparing the relatively small number of compounds identified in that first manuscript (10) with the over 10,000 individual molecular formulas that are typically identified in a single spectrum today. Our current efforts are directed to correlating these ultrahigh resolution mass spectrometry measurements with other techniques such as 13C NMR and 3-D excitation-emission fluorescence spectroscopy to identify chemical and biochemical signatures of climate change.