800 MHz NMR spectrometer (for liquids, with cryogenic probes)

• Subject Area: Atmospheric Science, Oceanography and Climate Research
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 493682661

At the Institute for Chemistry and Biology of the Marine Environment (University of Oldenburg) microbiological interactions and global element cycles are main research themes. For this research we engage in a voyage through scales, from molecules and single cells to ecosystems and global biogeochemical cycles. Processes occurring on the sub-micrometer scale in the ocean ultimately accumulate to planetary scale effects. Half of global photosynthetic production and respiration is carried out by unicellular life in the ocean. All organisms in the ocean excrete dissolved organic matter (DOM). Despite being a foundation for microbial life, the DOM reservoir contains more carbon than the entire biomass on land. The reason for this accumulation is unknown. DOM is the marine geometabolome, which is the entirety of small molecule metabolic products and their abiotic transformation products. The geometabolome is one of the most complex mixtures known, consisting of millions of compounds. A main focus of the planned NMR applications is the structural analysis of the marine geometabolome and its precursors, i.e. the exo- and endometabolomes of marine organisms. Conventional biochemical analysis solved the structure of only <1% of all compounds in the deep-sea geometabolome because it is a largely inseparable mixture. Currently, our main tool is ultrahigh-resolution mass spectrometry, combined with multivariate statistics and numerical modelling. To date, this approach yields the most comprehensive and detailed molecular data of the geometabolome. However, mass spectrometry provides only basic structural information. Isomers are not resolved, and the quantification of individual DOM constituents is usually impossible because we lack sufficient structural data and as such standards for quantification. High-field NMR overcomes many of these crucial limitations and yields highly complementary information to mass spectrometry. An intrinsic drawback of NMR spectroscopy, compared to ultrahigh-resolution mass spectrometry, is its low sensitivity and resolution. The large number of individual compounds of the geometabolome causes signal broadening and overlap, leading to unresolved signals in one-dimensional NMR spectra. Two- and three-dimensional high-field NMR is powerful in resolving discrete structural features even in complex mixtures. This detailed structural information is not accessible with any other analytical technique. Highest resolution, sensitivity and access to long instrument time are therefore main prerequisites for our research. The high-field NMR spectrometer will be embedded in a new “GeoMetabolomics Center” at the University of Oldenburg, which will be unique worldwide. We have a fair and open user concept through which 40% of the new facility will be available to external users from the marine and geosciences, but also from medicine, pharmacology, biochemistry, and other disciplines in the region and worldwide.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: 800-MHz-NMR-Spektrometer (für Flüssigkeiten mit kryogenen Probenköpfen)
• Instrumentation Group: 1740 Hochauflösende NMR-Spektrometer
• Applicant Institution: Carl von Ossietzky Universität Oldenburg
• Leader: Professor Dr. Thorsten Dittmar