Low-field 1H-NMR Relaxometer

• Subject Area: Agriculture, Forestry and Veterinary Medicine
• Term: Funded in 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 561967489

The Department of Natural and Environmental Sciences at the RPTU Kaiserslautern-Landau investigates the diverse and complex interactions between human activities and natural systems in terrestrial and aquatic ecosystems. Our studies place special emphasis on dynamic environmental processes at biogeochemical interfaces in porous media under the influence of anthropogenic stressors such as climate change, soil conditioners or pesticides. The mobility of water molecules in porous media (“water mobility”) is a key property and is determined by the physical surroundings of the water entrapped in the mineral phases of soils, sediments and pseudo-sands, but also in swellable organic matter or in anthropogenic (superabsorbent polymers) and biogenic (mucilage, biofilm) gel-forming substances. Information about the spatiotemporal variations of the water entrapment in porous media enables to study numerous environmental processes, such as redistribution of pore water in response to an environmental stressor, swelling and shrinking phenomena or changes of the wettability inside the porous media. The current device available at the iES Landau allows the determination of rotational water mobility in porous media by measuring the transverse and longitudinal relaxation times of water protons. However, a determination of the diffusion coefficient of water and a differentiation between swellable organic substances, swellable clay minerals and non-swellable minerals are currently not possible, what greatly limits the analysis of environmental samples in different swelling states or the investigation of wetting processes. The measurement of the trans-verse diffusion coefficient of water (D) and correlation measurements between transverse (D) and rotational (T2) mobility of water allow, amongst others, to determine the permeability of porous media and to differentiate between the surroundings of water, which may differ in their various physicochemical properties. This information is important to elucidate the morphological structure of porous samples and to investigate swelling and wetting processes, which depend on the interaction of water with the surrounding matrix. A low-field 1H NMR relaxometer equipped with a pulsed field gradient unit (PFG) and corresponding software will strongly support our research on deciphering dynamic environmental processes at biogeochemical interfaces in various natural systems and enable us to address previously unresolved research questions. This technology will also strengthen the collaboration with the chemistry faculty at RPTU, as the characterization of the interactions between water and synthetic porous inorganic materials is complementary to the methods used so far.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Niederfeld 1H-NMR-Relaxometer
• Instrumentation Group: 1740 Hochauflösende NMR-Spektrometer
• Applicant Institution: Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau
• Leader: Dr. Mathilde Knott