Our group hosts various tools for sampling and analysis of dissolved organic matter and related parameters. Central to the group is the 15 Tesla FT-ICR-MS to analyse molecular-level composition of DOM. Continuous method development and data evaluation are core tasks within the working group.
Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS)
Dissolved organic matter is a highly complex mixture and deciphering its molecular-level composition represents an analytical challenge. Fourier-Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR-MS) coupled to electrospray ionization is a valuable tool which can resolve the exact masses of intact molecules. We operate a Bruker Solarix XR with a 15 Tesla magnet. Electrospray Ionization (ESI) or Atmospheric Pressure Chemical Ionization (APCI) sources are available to ionize nonpolar to very polar compounds. The dynamically harmonized ParaCell allows the acquisition of spectra at extreme resolution (R>10,000,000). For routine analyses of large sample sets, a CTC PAL 3 autosampler can be connected to the instrument. Continuous method development and data evaluation routines for molecular formula assignment to the thousands of peaks detected per spectrum are core tasks within the working group.
- Dissolved organic matter molecular composition from marine or freshwater environments or laboratory experiments
- Characterization of oils and asphaltenes
- MS-MS experiments to characterize core structures
- Natural products characterization
Zark, M, Christoffers J and Dittmar T (2017). Molecular properties of deep-sea dissolved organic matter are predictable by the central limit theorem: evidence from tandem FT-ICR-MS. Marine Chemistry 191, 9-15.
Waska H, Koschinsky A and Dittmar T (2016) Fe- and Cu-complex formation with artificial ligands investigated by ultra-high resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS): Implications for natural metal-organic complex studies. Frontiers in Marine Science 3:1-19.
Pohlabeln A and Dittmar T (2015) Novel insights into the molecular structure of non-volatile marine dissolved organic sulfur. Marine Chemistry 168, 86-94.
Dittmar T and Paeng J (2009) A heat-induced molecular signature in marine dissolved organic matter. Nature Geoscience 2, 175-179.
Koch BP, Dittmar T, Witt M and Kattner G (2007) Fundamentals of molecular formula assignment to ultrahigh resolution mass data of natural organic matter. Analytical Chemistry 79, 1758-1763.
(+49) 441 - 798 3773
Nuclear Magnetic Resonance (NMR) Spectroscopy
High-field nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for the molecular level structural analysis of marine dissolved organic matter (DOM), a highly complex organic mixture known. Currently, we are performing all the NMR measurements of marine DOM samples at NMR-based Structural Biology, Max Planck Institute for Multidisciplinary Sciences, Göttingen. Our research focus is on the development and application of novel NMR methods that will provide further insights on the unexplored isomeric structural diversity of marine DOM from different marine environmentrs.
- Structural characterization of marine DOM
- Non-uniform sampling for speeding up the acquisition of 2D NMR spectra of marine DOM
- NMR analysis of geometabolome and exometabolome
- 31P and 15N NMR for the characterization of marine dissolved organic phosphorous (DOP) and dissolved organic nitrogen (DON), respectively
- Structure elucidation of isolated marine Natural products
Seidel M, Vemulapalli SPB, Mathieu D and Dittmar T (2022) Marine dissolved organic matter shares thousands of molecular formulae yet differs structurally across major water masses. Environmental Science & Technology 56, 3758-3769. doi.org/10.1021/acs.est.1c04566
Klose D,# Vemulapalli SPB,# Richman M,# Rudnick S, Aisha V, Abayev M, Chemerovski M, Shviro M, Zitoun D, Majer K, Wili N, Goobes G, Griesinger C, Jeschke G and Rahimipour S (2022) Cu2+-Induced self-assembly and amyloid formation of a cyclic d,l-α-peptide: structure and function. Physical Chemistry Chemical Physics 24, 6699-6715. doi.org/10.1039/D1CP05415E
(#Shared co-first authors)
Vemulapalli SPB, Becker S, Griesinger C and Rezaei-Ghaleh N (2021) Combined High-Pressure and Multiquantum NMR and Molecular Simulation Propose a Role for N-Terminal Salt Bridges in Amyloid-Beta. Journal of Physical Chemistry Letters 12, 9933-9939. doi.org/10.1021/acs.jpclett.1c02595
Vemulapalli SPB, Fuentes-Monteverde JC, Karschin N, Oji T, Griesinger C and Wolkenstein K (2021) Structure and absolute configuration of phenanthro-perylene quinone pigments from the deep-sea crinoid hypalocrinus naresianus. Marine Drugs 19, 445. doi.org/10.3390/md19080445
Sahithya Phani Babu Vemulapalli
PHONE: (49) 441-798-3380
Dissolved organic carbon (DOC) / Dissolved organic nitrogen (DON) Analyzer
The Shimadzu Analysers provide information on the bulk concentration of Dissolved Organic Carbon (DOC, defined as organic carbon that passes through a 0.7 µm filter) and total dissolved nitrogen (TDN). Based on the “high-temperature combustion method” (720°C), organic carbon is oxidized completely to CO2, which is susequently measured with an Infra-Red Detector. Nitrogen in organic molecules and inorganic forms of nitrogen (TDN) are equally oxidized, and detected as NO2 via chemoluminescence.
Analyses are routinely performed with water from various locations, i.e. open ocean, north sea, black sea, lakes, rivers, swamps, hydrothermal vents, etc. Also analysis of samples with specific requirements is possible, e.g. measuring the DOC/TDN content of hailstones in extremely low volumes (100 µL).
List of people involved:
Sugimura and Suzuki (1988): A high-temperature catalytic oxidation method for the determination of non-volatile dissolved organic carbon in seawater by direct injection of a liquid sample. Marine Chemistry 24: 105-131
Aron Stubbins and Thorsten Dittmar (2012) Low volume quantification of dissolved organic carbon and dissolved nitrogen. Limnol. Oceanogr.: Methods 10, 2012, 347–352
Ultra performance liquid chromatography (UPLC)
Dissolved organic matter contains a suite of organic molecules that can be separated and quantified using liquid chromatography. Prominent examples are individual amino acids and carbohydrates. There are also components in DOM that can be traced through characteristic products after specific chemical treatment, e.g. dissolved lignin (lignin phenols) and dissolved black carbon (benzenepolycarboxylic acids).
Ultra performance liquid chromatography (UPLC) uses the principles of high performance liquid chromatography (HPLC) but works with pressures of up to 1000 bar. Applying such high pressure, particle sizes in the separation columns can be much smaller (< 2 µm), which increases separation while reducing run time, sample volume and solvent use.
UPLC system I:
Waters Acquity UPLC®: Binary Solvent Manager, Sample Manager, Column Manager, PDA eλ Detector
UPLC system I is equipped with a photodiode array absorbance detector. This system is used for routine analysis of benzenepolycarboxylic acids (BPCA). The column manager can hold up to four different separation columns, providing a helpful tool for method development.
UPLC system II:
Waters Acquity UPLC®: Binary Solvent Manager, Sample Manager, FLR Detector
UPLC system II is equipped with a fluorescence detector. Main application of this system is amino acid analysis.
0441 - 798 3365
Benzenepolycarboxylic acids (dissolved black carbon):
Dittmar, T. (2008) The molecular level determination of black carbon in marine dissolved organic matter. Organic Geochemistry 39: 396-407
Jaffé, R., Ding, Y., Niggemann, J., Vähätalo, A.V., Campbell, J., Dittmar, T. (2013) Global charcoal mobilization from soils via dissolution and riverine transport to the oceans. Science 340(6130): 345-347
Lignin phenols (lignin):
Chmiel, H.E., Niggemann, J., Kokic, J., Ferland, M.-E., Dittmar, T., Sobek, S. (2015) Uncoupled organic matter burial and quality in boreal lake sediments over the Holocene. Journal of Geophysical Research: Biogeosciences 120: 1751-1763
De la Cruz, F.B., Dittmar, T., Niggemann, J., Osburn, C.L., Barlaz, M.A. (2015) Evaluation of copper oxide oxidation for quantification of lignin in municipal solid waste. Environmental Engineering Science 32: 486-496
High performance liquid chromatography (HPLC)
Dissolved organic matter contains a suite of organic molecules that can be separated and quantified using liquid chromatography. Prominent examples are individual amino acids and carbohydrates.
Carbohydrate analysis uses a specific HPLC application called high-performance anion-exchange chromatography (HPAE), working at high pH and using strong anion exchange stationary phases. Pulsed amperometric detection (PAD) is an electrochemical detection method that has been optimized for carbohydrate analysis.
Thermo Scientific Dionex ICS-5000+: SP Single Pumps (gradient pump with degassing unit), DC Chromatography Compartment, ED Electrochemical Detector, AS-AP Autosampler.
0441 - 798 3365
To study photochemical transformation of dissolved organic molecules under controlled conditions, we have set up a closed irradiation.
The setup consists of several parts:
- Black box to shield environment from UV irradiation
- Water bath with heater and flow-through pump to keep temperature level constant, a fan is mounted on the back wall for air exchange
- 8 UVA-340 fluorescent tubes (Q-Lab), distance to sample can be adjusted
- Quartz tubes (~170 mL volume) to irradiate aqueous samples
0441 - 798 3768
We use our voltammetry system primarily to investigate natural and artificial metal-ligand equilibria. A common approach is competitive ligand equilibration-adsorptive cathodic stripping voltammetry (CLE-ACSV). For this method, a natural water sample is titrated with increasing amounts of a trace metal (for example, Cu or Fe) until the contained ligands are saturated. Exchangeable and excess metal ions are captured by an added, known ligand (for example, salicylaldoxime, SA) which forms a complex detectable by voltammetry. Based on the resulting titration curve, (bulk) conditional stability constants and complexing capacities of natural water samples can be derived.
List of people involved:
H. Waska, A. Koschinsky, and T. Dittmar (2016) Fe- and Cu-complex formation with artificial ligands investigated by ultra-high resolution Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS): Implications for metal-organic complex studies. Front. Mar. Sci. 3, 119.
H. Waska, A. Koschinsky, M. J. R. Chancho, and T. Dittmar (2015) Investigating the potential of solid-phase extraction and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) for the isolation and identification of dissolved metal-organic complexes from natural waters. Mar. Chem. 173: 78-92.
Dr. Hannelore Waska
0441 - 798 3159
Our lab routinely performes sampling at field sites e.g. in the North and Wadden Sea, such as Janssand tidal flat or Spiekeroog beach. These environment require specific equipment to facilitate research campaigns, which are available and frequently used in our group. A suite of sturdy stainless steel push-point samplers for pore water collection have been developed which can be deployed at different sediment depths (< 2 m), and be quickly retrieved. They are equipped with 50 µm mesh nets to minimize sediment entrainment. Also, sampling under exclusion of oxygen is possible, by using a tightly sealed pumping system and inline filters. Seepage meters for the collection of submarine groundwater discharge were designed to be trace-metal free.
Our instrumentation also includes a field fluorometer (Aquafluor, Turner instruments), a GPS (Garmin Colorado 400c), and a water-proof camera.
List of people involved:
H. Waska, J. Greskowiak, J. Ahrens, M. Beck, S. Ahmerkamp, P. Böning, H.-J. Brumsack, J. Degenhardt, C. Ehlert, B. Engelen, N. Grünenbaum, M. Holtappels, K. Pahnke, H. K. Marchant, G. Massmann, D. Meier, B. Schnetger, K. Schwalfenberg, H. Simon, V. Vandieken, O. Zielinski, T. Dittmar (2019). Spatial and temporal patterns of pore water chemistry in the inter-tidal zone of a high energy beach. Front. Mar. Sci. 6: 154
A. Linkhorst, T. Dittmar, H. Waska (2017) Molecular fractionation of dissolved organic matter in a shallow subterranean estuary: The role of the iron curtain. Environ. Sci. Technol. 51 (3), 1312-1320.
M. Seidel, M. Beck, J. Greskowiak, T. Riedel, H. Waska, I. G. N. Suryaputra, B. Schnetger, J. Niggemann, M. Simon, and T. Dittmar (2015) Benthic-pelagic coupling of nutrients and dissolved organic matter composition in an intertidal sandy beach. Mar. Chem. 176: 150-163.
Dr. Hannelore Waska
0441 - 798 3348