Article
Multidisciplinary Sciences
Sebastian Z. Kiss, Neil MacKinnon, Jan G. Korvink
Summary: A compact double resonant chip stack system has been developed to achieve in situ dynamic nuclear polarisation of small sample volumes, overcoming instrumental barriers to NMR detection for point-of-care applications. This technology allows for signal enhancements up to -60 relative to thermal equilibrium at a microwave power level of 0.5W.
SCIENTIFIC REPORTS
(2021)
Article
Chemistry, Physical
Maik Reinhard, Marcel Levien, Marina Bennati, Tomas Orlando
Summary: Dynamic nuclear polarization (DNP) is a method to enhance the low sensitivity of nuclear magnetic resonance (NMR) by transferring spin polarization from electron spins to nuclear spins. The formation of weak complexes between BDPA and PPh3 can result in large NMR signal enhancements.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Biochemical Research Methods
Murari Soundararajan, Thierry Dubroca, Johan van Tol, Stephen Hill, Lucio Frydman, Sungsool Wi
Summary: This study presents 1H-detected NMR experiments on relatively large liquid volumes at high fields using ODNP enhancements. By utilizing scalar couplings between 13C and 1H, the polarization transfer between nuclei was achieved, resulting in higher sensitivity at higher frequencies.
JOURNAL OF MAGNETIC RESONANCE
(2022)
Article
Chemistry, Multidisciplinary
Mattia Negroni, Ertan Turhan, Thomas Kress, Morgan Ceillier, Sami Jannin, Dennis Kurzbach
Summary: Nuclear magnetic resonance (NMR) spectroscopy is a crucial technique for molecular structure determination in solution. Dissolution dynamic nuclear polarization (DDNP) is a versatile approach that can achieve signal enhancements of over 10,000-fold. However, the applicability of DDNP is limited by paramagnetic relaxation enhancements (PREs) caused by co-dissolved radicals. Using potassium nitrosodisulfonate (Fremy's salt) as a polarization agent can solve this problem and has shown promising potential.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2022)
Article
Food Science & Technology
Alper Soyler, Sevil Cikrikci, Cagri Cavdaroglu, Dylan Bouillaud, Jonathan Farjon, Patrick Giraudeau, Mecit H. Oztop
Summary: This study investigated the application of benchtop NMR spectroscopy in analyzing milk in an industrial context, focusing on production quality and product differentiation. Through quantitative online NMR spectroscopy, lactose hydrolysis in milk was tracked and different milk samples were successfully differentiated based on their properties.
LWT-FOOD SCIENCE AND TECHNOLOGY
(2021)
Article
Chemistry, Physical
Marcel Levien, Maik Reinhard, Markus Hiller, Igor Tkach, Marina Bennati, Tomas Orlando
Summary: There is a large variation in liquid DNP performance among common organic radicals used as polarizing agents, with a factor of about five in coupling factor. A comparative study of H-1 and C-13 DNP in model systems shows the impact of spin density distribution and the accessibility of radical sites by the target molecule.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
Article
Chemistry, Multidisciplinary
Felipe Saenz, Mika Tamski, Jonas Milani, Christophe Roussel, Holger Frauenrath, Jean-Philippe Ansermet
Summary: Overhauser Dynamic Nuclear Polarization (O-DNP) is a technique that transfers spin polarization from unpaired electrons to surrounding nuclei in solution, significantly increasing the nuclear magnetic resonance signal intensity. By using specific types of radicals as polarizing agents and electrochemically removing unpaired electrons on demand, relaxation of the hyperpolarized state can be avoided. This approach potentially allows for the development of highly tunable radicals for electrochemical DNP.
CHEMICAL COMMUNICATIONS
(2022)
Review
Chemistry, Physical
Nandita Abhyankar, Veronika Szalai
Summary: Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for studying molecular structure and dynamics of materials, but its low sensitivity is due to low spin polarization. Dynamic nuclear polarization (DNP) can significantly increase sensitivity by hyperpolarizing nuclear spins using a paramagnetic matrix. While DNP NMR is commonly used in solid-state NMR, its application in liquid-state samples is still underexplored.
JOURNAL OF PHYSICAL CHEMISTRY B
(2021)
Article
Biochemistry & Molecular Biology
Anthony Mancuso, Mehrdad Pourfathi, Ryan M. Kiefer, Michael C. Noji, Sarmad Siddiqui, Enri Profka, Charles N. Weber, Austin Pantel, Stephen J. Kadlecek, Rahim Rizi, Terence P. F. Gade
Summary: This study introduces new methods for studying cancer cell metabolism using hyperpolarized C-13 magnetic resonance spectroscopy, enabling quantitative studies at low oxygen concentrations. Experimental results showed that radial flow perfusion system resulted in more uniform cell mass oxygen profiles compared to conventional axial flow, emphasizing the importance of avoiding large oxygen gradients in cell perfusion experiments. The metabolism of HP [1-C-13]pyruvate was significantly different between the two flow configurations, indicating the impact of oxygen gradients on metabolic outcomes.
Article
Biochemical Research Methods
Bing Wu, Ruud L. E. G. Aspers, Arno P. M. Kentgens, Evan Wenbo Zhao
Summary: By using high-field operando NMR analysis, researchers gained insights into the working mechanisms of RFBs and improved battery performance. However, the high cost and large footprint of the high-field NMR system limited its implementation. As an alternative, they demonstrated an operando NMR study of an RFB using a low-cost and compact 43 MHz benchtop system, obtaining different results from high-field NMR experiments and providing new insights into RFBs. They concluded that the benchtop NMR system has sufficient capabilities for operando studies of RFBs and could be widely applied in flow electrochemistry research.
JOURNAL OF MAGNETIC RESONANCE
(2023)
Article
Food Science & Technology
Ignacio Migues, Fernando Rivas, Guillermo Moyna, Simon D. Kelly, Horacio Heinzen
Summary: Recent advances in NMR technology have made low-field benchtop NMR systems suitable for use in research and quality-control laboratories. In this study, a method for predicting consumer acceptability of mandarins using high-field NMR was adapted to benchtop NMR systems, and comparable results were obtained. The lower cost of benchtop NMR systems makes them a useful tool for cultivators in selecting new cultivars.
Review
Chemistry, Analytical
Diego Galvan, Leticia Magalhaes de Aguiar, Evandro Bona, Federico Marini, Mario Henrique M. Killner
Summary: Low-field nuclear magnetic resonance (NMR) has three modalities: spectroscopy, imaging, and relaxometry. Spectroscopy, also known as benchtop NMR, has recently undergone instrumental development and emerged as a powerful analytical tool in process analytical control (PAC). The successful application of NMR devices in various fields is closely related to their coupling with different chemometric methods.
ANALYTICA CHIMICA ACTA
(2023)
Article
Chemistry, Multidisciplinary
Flora Nagy, Evelin Santa-Bell, Monica Jipa, Gabor Hornyanszky, Andras Szilagyi, Krisztina Laszlo, Gabriel Katona, Csaba Paizs, Laszlo Poppe, Diana Balogh-Weiser
Summary: Nanostructured biocatalysts were created using multi-functionalized silica nanoparticles to form robust micro-sized particles with beneficial internal structure. Systematic surface modification enabled cross-linking of enzymes to create macroporous microparticles, addressing weaknesses of traditional enzyme aggregates and showing potential for industrial applications.
Article
Chemistry, Multidisciplinary
Diego Gauto, Ons Dakhlaoui, Ildefonso Marin-Montesinos, Sabine Hediger, Gael De Paepe
Summary: High-field dynamic nuclear polarization is expanding the applications of solid-state NMR in surface chemistry, materials science, and structural biology. Targeted DNP approaches, where paramagnets are specifically located on biomolecular systems, show potential for improving NMR sensitivity without the need for glass-forming DNP matrices. This technique is particularly useful for studying diluted biomolecular systems like membrane proteins in their lipidic environment and extracting structural information through paramagnetic relaxation enhancement.
Article
Chemistry, Multidisciplinary
Andrei Gurinov, Benedikt Sieland, Andrey Kuzhelev, Hossam Elgabarty, Thomas D. Kuehne, Thomas Prisner, Jan Paradies, Marc Baldus, Konstantin L. Ivanov, Svetlana Pylaeva
Summary: A novel set of polarizing agents - mixed-valence compounds have been investigated through theoretical and experimental methods, showcasing their performance in high-field dynamic nuclear polarization (DNP) NMR experiments in the solid state. These compounds, with molecular mobility persisting even in solids, can be used to conduct Overhauser-DNP experiments in the solid state, providing favorable conditions for dynamic nuclear polarization formation at ultra-high magnetic fields.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Multidisciplinary
J. Eills, E. Cavallari, R. Kircher, G. Di Matteo, C. Carrera, L. Dagys, M. H. Levitt, K. L. Ivanov, S. Aime, F. Reineri, K. Muennemann, D. Budker, G. Buntkowsky, S. Knecht
Summary: This study introduces a novel H-1 imaging method in which hyperpolarized spin order is released for imaging through a specific biochemical reaction, while suppressing background signals from water. It allows for hyperpolarized imaging without the need for low-abundance, low-sensitivity heteronuclei.
ANGEWANDTE CHEMIE-INTERNATIONAL EDITION
(2021)
Article
Chemistry, Medicinal
Thomas Specht, Kerstin Muennemann, Hans Hasse, Fabian Jirasek
Summary: Automated methods using support vector classification from NMR spectra can accurately identify and quantify the structural groups in pure components and mixtures. The methods demonstrate excellent predictions for pure components not included in the training set as well as mixtures.
JOURNAL OF CHEMICAL INFORMATION AND MODELING
(2021)
Article
Multidisciplinary Sciences
Stephan Knecht, John W. Blanchard, Danila Barskiy, Eleonora Cavallari, Laurynas Dagys, Erik Van Dyke, Maksim Tsukanov, Bea Bliemel, Kerstin Muennemann, Silvio Aime, Francesca Reineri, Malcolm H. Levitt, Gerd Buntkowsky, Alexander Pines, Peter Bluemler, Dmitry Budker, James Eills
Summary: This study discusses the techniques of hyperpolarizing fumarate using dissolution dynamic nuclear polarization and parahydrogen-induced polarization, as well as the method of purifying pure solid fumarate from impurities through acid precipitation.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Analytical
Raphael Kircher, Hans Hasse, Kerstin Muennemann
Summary: Analysis of fast-flowing liquids with NMR spectroscopy is challenging due to poor signal intensity caused by short residence times in the spectrometer's magnetic field. Different methods were experimentally studied to counteract this issue, with Overhauser dynamic nuclear polarization (ODNP) proving to be effective in enhancing signal intensity even at high flow rates.
ANALYTICAL CHEMISTRY
(2021)
Article
Engineering, Chemical
Daniel Bellaire, Kerstin Munnemann, Hans Hasse
Summary: In this study, nuclear magnetic resonance imaging (MRI) was used to measure the mutual diffusion coefficient of methane in toluene at 298 K. The concentration field was monitored using two-dimensional MRI after dissolving gaseous methane in liquid toluene. To overcome the low concentration of methane, a chemical shift-selective pulse sequence was employed. The resulting diffusion coefficient, determined from the temporally and spatially resolved concentration data based on Fick's second law, is in good agreement with reference data. The study concludes that MRI experiments are suitable for quantitative studies of mutual diffusion in liquid mixtures, even in challenging applications like the one investigated here.
CHEMICAL ENGINEERING SCIENCE
(2022)
Article
Thermodynamics
Daniel Bellaire, Oliver Grossmann, Kerstin Muennemann, Hans Hasse
Summary: The diffusion coefficients of carbon dioxide and methane in various solvents were studied using PFG-NMR and molecular dynamics simulations. The results were compared with literature data and prediction methods.
JOURNAL OF CHEMICAL THERMODYNAMICS
(2022)
Article
Chemistry, Multidisciplinary
Daniel Bellaire, Stefan Thielen, Christoph Burkhart, Kerstin Muennemann, Hans Hasse, Bernd Sauer
Summary: This study investigates the compatibility between rubber material of radial shaft seals and lubricants, as well as the diffusion process of the lubricant into the rubber. Magnetic resonance imaging (MRI) is used to quantify the penetration depth of the lubricant and provide detailed insights into the swelling process of the seal.
Article
Engineering, Chemical
Silvie Mueller, Eckhard Stroefer, Maximilian Kohns, Kerstin Muennemann, Erik von Harbou, Hans Hasse
Summary: A laboratory-scale DBD cold plasma reactor was designed and used to study the influence of specific energy input (SEI) on the product spectrum of partial oxidation of methane. The experimental results obtained are valuable for developing reaction kinetic models of this reaction in DBD plasma reactors.
PLASMA CHEMISTRY AND PLASMA PROCESSING
(2023)
Article
Chemistry, Multidisciplinary
Thomas Specht, Justus Arweiler, Johannes Stueber, Kerstin Muennemann, Hans Hasse, Fabian Jirasek
Summary: Nuclear magnetic resonance (NMR) spectroscopy is a powerful tool for qualitative and quantitative analysis. NMR fingerprinting, a group-based approach, allows easier identification and quantification of structural groups in mixtures. This study demonstrates that automated NMR fingerprinting, based on machine-learning support vector classification, using standard NMR spectra, can accurately determine the composition of mixtures.
MAGNETIC RESONANCE IN CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Johnnie Phuong, Zeno Romero, Hans Hasse, Kerstin Muennemann
Summary: Benchtop NMR spectroscopy is attractive for process monitoring, but it has drawbacks that can be overcome by using H-1-C-13 polarization transfer methods. This study demonstrates the high potential of polarization transfer methods for quantitative process analysis, especially for flowing samples.
MAGNETIC RESONANCE IN CHEMISTRY
(2023)
Article
Chemistry, Multidisciplinary
Ellen Steimers, Yevgen Matviychuk, Anne Friebel, Kerstin Muennemann, Erik von Harbou, Daniel J. Holland
Summary: This study introduces two NMR methods, 2D non-uniform sampling and model-based fitting approach, to overcome challenges of low resolution and overlapping peaks in NMR spectra. By applying these methods to analyze complex reaction mixtures, comparable results to high-field data can be obtained.
MAGNETIC RESONANCE IN CHEMISTRY
(2021)