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Reinhard M, Levien M, Bennati M, Orlando T. Large 31P-NMR enhancements in liquid state dynamic nuclear polarization through radical/target molecule non-covalent interaction. Phys Chem Chem Phys 2022; 25:822-828. [PMID: 36511338 PMCID: PMC9768845 DOI: 10.1039/d2cp04092a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Dynamic nuclear polarization (DNP) is a method to enhance the low sensitivity of nuclear magnetic resonance (NMR) via spin polarization transfer from electron spins to nuclear spins. In the liquid state, this process is mediated by fast modulations of the electron-nuclear hyperfine coupling and its efficiency depends strongly on the applied magnetic field. A peculiar case study is triphenylphosphine (PPh3) dissolved in benzene and doped with BDPA radical because it gives 31P-NMR signal enhancements of two orders of magnitude up to a magnetic field of 14.1 T. Here we show that the large 31P enhancements of BDPA/PPh3 in benzene at 1.2 T (i) decrease when the moieties are dissolved in other organic solvents, (ii) are strongly reduced when using a nitroxide radical, and (iii) vanish with pentavalent 31P triphenylphosphine oxide. Those experimental observations are rationalized with numerical calculations based on density functional theory that show the tendency of BDPA and PPh3 to form a weak complex via non-covalent interaction that leads to large hyperfine couplings to 31P (ΔAiso ≥ 13 MHz). This mechanism is hampered in other investigated systems. The case study of 31P-DNP in PPh3 is an important example that extends the current understanding of DNP in the liquids state: non-covalent interactions between radical and target can be particularly effective to obtain large NMR signal enhancements.
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Affiliation(s)
- Maik Reinhard
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany,Department of Chemistry, Georg-August-University, Tammannstraße 4GöttingenGermany
| | - Marcel Levien
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany,Department of Chemistry, Georg-August-University, Tammannstraße 4GöttingenGermany
| | - Marina Bennati
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany,Department of Chemistry, Georg-August-University, Tammannstraße 4GöttingenGermany
| | - Tomas Orlando
- ESR Spectroscopy Group, Max Planck Institute for Multidisciplinary Sciences, Am Faßberg 11GöttingenGermany
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2
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Eills J, Hale W, Utz M. Synergies between Hyperpolarized NMR and Microfluidics: A Review. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 128:44-69. [PMID: 35282869 DOI: 10.1016/j.pnmrs.2021.09.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/10/2021] [Accepted: 09/11/2021] [Indexed: 06/14/2023]
Abstract
Hyperpolarized nuclear magnetic resonance and lab-on-a-chip microfluidics are two dynamic, but until recently quite distinct, fields of research. Recent developments in both areas increased their synergistic overlap. By microfluidic integration, many complex experimental steps can be brought together onto a single platform. Microfluidic devices are therefore increasingly finding applications in medical diagnostics, forensic analysis, and biomedical research. In particular, they provide novel and powerful ways to culture cells, cell aggregates, and even functional models of entire organs. Nuclear magnetic resonance is a non-invasive, high-resolution spectroscopic technique which allows real-time process monitoring with chemical specificity. It is ideally suited for observing metabolic and other biological and chemical processes in microfluidic systems. However, its intrinsically low sensitivity has limited its application. Recent advances in nuclear hyperpolarization techniques may change this: under special circumstances, it is possible to enhance NMR signals by up to 5 orders of magnitude, which dramatically extends the utility of NMR in the context of microfluidic systems. Hyperpolarization requires complex chemical and/or physical manipulations, which in turn may benefit from microfluidic implementation. In fact, many hyperpolarization methodologies rely on processes that are more efficient at the micro-scale, such as molecular diffusion, penetration of electromagnetic radiation into a sample, or restricted molecular mobility on a surface. In this review we examine the confluence between the fields of hyperpolarization-enhanced NMR and microfluidics, and assess how these areas of research have mutually benefited one another, and will continue to do so.
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Affiliation(s)
- James Eills
- Institute for Physics, Johannes Gutenberg University, D-55090 Mainz, Germany; GSI Helmholtzzentrum für Schwerionenforschung GmbH, Helmholtz-Institut Mainz, 55128 Mainz, Germany.
| | - William Hale
- Department of Chemistry, University of Florida, 32611, USA
| | - Marcel Utz
- School of Chemistry, University of Southampton, SO17 1BJ, UK.
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3
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Korchak S, Kaltschnee L, Dervisoglu R, Andreas L, Griesinger C, Glöggler S. Spontaneous Enhancement of Magnetic Resonance Signals Using a RASER. Angew Chem Int Ed Engl 2021; 60:20984-20990. [PMID: 34289241 PMCID: PMC8518078 DOI: 10.1002/anie.202108306] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Indexed: 11/06/2022]
Abstract
Nuclear magnetic resonance is usually drastically limited by its intrinsically low sensitivity: Only a few spins contribute to the overall signal. To overcome this limitation, hyperpolarization methods were developed that increase signals several times beyond the normal/thermally polarized signals. The ideal case would be a universal approach that can signal enhance the complete sample of interest in solution to increase detection sensitivity. Here, we introduce a combination of para-hydrogen enhanced magnetic resonance with the phenomenon of the RASER: Large signals of para-hydrogen enhanced molecules interact with the magnetic resonance coil in a way that the signal is spontaneously converted into an in-phase signal. These molecules directly interact with other compounds via dipolar couplings and enhance their signal. We demonstrate that this is not only possible for solvent molecules but also for an amino acid.
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Affiliation(s)
- Sergey Korchak
- NMR Signal Enhancement GroupMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
- Center for Biostructural Imaging of Neurodegeneration of UMGVon-Siebold-Str. 3A37075GöttingenGermany
| | - Lukas Kaltschnee
- NMR Signal Enhancement GroupMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
- Center for Biostructural Imaging of Neurodegeneration of UMGVon-Siebold-Str. 3A37075GöttingenGermany
| | - Riza Dervisoglu
- Research Group for Solid State NMRMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
| | - Loren Andreas
- Research Group for Solid State NMRMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
| | - Christian Griesinger
- Department of NMR-based Structural BiologyMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
| | - Stefan Glöggler
- NMR Signal Enhancement GroupMax Planck Institute for Biophysical ChemistryAm Fassberg 1137077GöttingenGermany
- Center for Biostructural Imaging of Neurodegeneration of UMGVon-Siebold-Str. 3A37075GöttingenGermany
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4
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Korchak S, Kaltschnee L, Dervisoglu R, Andreas L, Griesinger C, Glöggler S. Spontaneous Enhancement of Magnetic Resonance Signals Using a RASER. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202108306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Sergey Korchak
- NMR Signal Enhancement Group Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG Von-Siebold-Str. 3A 37075 Göttingen Germany
| | - Lukas Kaltschnee
- NMR Signal Enhancement Group Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG Von-Siebold-Str. 3A 37075 Göttingen Germany
| | - Riza Dervisoglu
- Research Group for Solid State NMR Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
| | - Loren Andreas
- Research Group for Solid State NMR Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
| | - Christian Griesinger
- Department of NMR-based Structural Biology Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
| | - Stefan Glöggler
- NMR Signal Enhancement Group Max Planck Institute for Biophysical Chemistry Am Fassberg 11 37077 Göttingen Germany
- Center for Biostructural Imaging of Neurodegeneration of UMG Von-Siebold-Str. 3A 37075 Göttingen Germany
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5
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Abhyankar N, Szalai V. Challenges and Advances in the Application of Dynamic Nuclear Polarization to Liquid-State NMR Spectroscopy. J Phys Chem B 2021; 125:5171-5190. [PMID: 33960784 PMCID: PMC9871957 DOI: 10.1021/acs.jpcb.0c10937] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful method to study the molecular structure and dynamics of materials. The inherently low sensitivity of NMR spectroscopy is a consequence of low spin polarization. Hyperpolarization of a spin ensemble is defined as a population difference between spin states that far exceeds what is expected from the Boltzmann distribution for a given temperature. Dynamic nuclear polarization (DNP) can overcome the relatively low sensitivity of NMR spectroscopy by using a paramagnetic matrix to hyperpolarize a nuclear spin ensemble. Application of DNP to NMR can result in sensitivity gains of up to four orders of magnitude compared to NMR without DNP. Although DNP NMR is now more routinely utilized for solid-state (ss) NMR spectroscopy, it has not been exploited to the same degree for liquid-state samples. This Review will consider challenges and advances in the application of DNP NMR to liquid-state samples. The Review is organized into four sections: (i) mechanisms of DNP NMR relevant to hyperpolarization of liquid samples; (ii) applications of liquid-state DNP NMR; (iii) available detection schemes for liquid-state samples; and (iv) instrumental challenges and outlook for liquid-state DNP NMR.
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Affiliation(s)
- Nandita Abhyankar
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Veronika Szalai
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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Levien M, Hiller M, Tkach I, Bennati M, Orlando T. Nitroxide Derivatives for Dynamic Nuclear Polarization in Liquids: The Role of Rotational Diffusion. J Phys Chem Lett 2020; 11:1629-1635. [PMID: 32003568 PMCID: PMC7307959 DOI: 10.1021/acs.jpclett.0c00270] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2019] [Accepted: 01/31/2020] [Indexed: 06/07/2023]
Abstract
Polarization transfer efficiency in liquid-state dynamic nuclear polarization (DNP) depends on the interaction between polarizing agents (PAs) and target nuclei modulated by molecular motions. We show how translational and rotational diffusion differently affect the DNP efficiency. These contributions were disentangled by measuring 1H-DNP enhancements of toluene and chloroform doped with nitroxide derivatives at 0.34 T as a function of either the temperature or the size of the PA. The results were employed to analyze 13C-DNP data at higher fields, where the polarization transfer is also driven by the Fermi contact interaction. In this case, bulky nitroxide PAs perform better than the small TEMPONE radical due to structural fluctuations of the ring conformation. These findings will help in designing PAs with features specifically optimized for liquid-state DNP at various magnetic fields.
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Affiliation(s)
- M. Levien
- Research
Group EPR Spectroscopy, Max Planck Institute
for Biophysical Chemistry, Göttingen 37077, Germany
- Department
of Chemistry, Georg-August University, Göttingen 37077, Germany
| | - M. Hiller
- Research
Group EPR Spectroscopy, Max Planck Institute
for Biophysical Chemistry, Göttingen 37077, Germany
| | - I. Tkach
- Research
Group EPR Spectroscopy, Max Planck Institute
for Biophysical Chemistry, Göttingen 37077, Germany
| | - M. Bennati
- Research
Group EPR Spectroscopy, Max Planck Institute
for Biophysical Chemistry, Göttingen 37077, Germany
- Department
of Chemistry, Georg-August University, Göttingen 37077, Germany
| | - T. Orlando
- Research
Group EPR Spectroscopy, Max Planck Institute
for Biophysical Chemistry, Göttingen 37077, Germany
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7
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Tijssen KCH, van Weerdenburg BJA, Zhang H, Janssen JWG, Feiters MC, van Bentum PJM, Kentgens APM. Monitoring Heterogeneously Catalyzed Hydrogenation Reactions at Elevated Pressures Using In-Line Flow NMR. Anal Chem 2019; 91:12636-12643. [PMID: 31508941 PMCID: PMC6796828 DOI: 10.1021/acs.analchem.9b00895] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
We present a novel setup that can be used for the in-line monitoring of solid-catalyzed gas-liquid reactions. The method combines the high sensitivity and resolution of a stripline NMR detector with a microfluidic network that can withstand elevated pressures. In our setup we dissolve hydrogen gas in the solvent, then flow it with the added substrate through a catalyst cartridge, and finally flow the reaction mixture directly through the stripline NMR detector. The method is quantitative and can be used to determine the solubility of hydrogen gas in liquids; it allows in-line monitoring of hydrogenation reactions and can be used to determine the reaction kinetics of these reactions. In this work, as proof of concept we demonstrate the optimization of the Pd-catalyzed hydrogenation reactions of styrene, phenylacetylene, cyclohexene, and hex-5-en-2-one in a microfluidic context.
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Affiliation(s)
| | | | - Hainan Zhang
- Mesoscale Chemical Systems, Mesa+ Institute for Nanotechnology , University of Twente , Enschede , The Netherlands
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8
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Dubroca T, Wi S, van Tol J, Frydman L, Hill S. Large volume liquid state scalar Overhauser dynamic nuclear polarization at high magnetic field. Phys Chem Chem Phys 2019; 21:21200-21204. [PMID: 31310269 DOI: 10.1039/c9cp02997d] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Dynamic Nuclear Polarization (DNP) can increase the sensitivity of Nuclear Magnetic Resonance (NMR), but it is challenging in the liquid state at high magnetic fields. In this study we demonstrate significant enhancements of NMR signals (up to 70 on 13C) in the liquid state by scalar Overhauser DNP at 14.1 T, with high resolution (∼0.1 ppm) and relatively large sample volume (∼100 μL).
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9
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van Zelst FHM, van Meerten SGJ, van Bentum PJM, Kentgens APM. Hyphenation of Supercritical Fluid Chromatography and NMR with In-Line Sample Concentration. Anal Chem 2018; 90:10457-10464. [PMID: 30080387 PMCID: PMC6127797 DOI: 10.1021/acs.analchem.8b02357] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
![]()
By
coupling supercritical fluid chromatography (SFC) and nuclear
magnetic resonance (NMR) in-line, a powerful analytical method arises
that enables chemically specific analysis of a broad range of complex
mixtures. However, during chromatography, the compounds are diluted
in the mobile phase, in this case supercritical CO2 (scCO2), often resulting in concentrations that are too low to be
detected by NMR spectroscopy or at least requiring excessive signal
averaging. We present a hyphenated SFC-NMR setup with an integrated
approach for concentrating samples in-line, which are diluted in scCO2 during chromatography. This in-line concentration is achieved
by controlled in-line expansion of the scCO2. As a proof
of concept four isomers of vitamin E (tocopherol) were isolated by
SFC, concentrated in-line by expanding CO2 from 120 to
50 bar, and finally shuttled to the NMR spectrometer fitted with a
dedicated probehead for spectroscopic characterization of microfluidic
samples. The abundant isomers were readily detected, supporting the
viability of SFC-NMR as a powerful analytical tool.
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Affiliation(s)
- F H M van Zelst
- Institute for Molecules and Materials (IMM) , Radboud University , Nijmegen 6525 AJ , The Netherlands.,TA-COAST , Science Park 904 , Amsterdam 1098 XH , The Netherlands
| | - S G J van Meerten
- Institute for Molecules and Materials (IMM) , Radboud University , Nijmegen 6525 AJ , The Netherlands.,TA-COAST , Science Park 904 , Amsterdam 1098 XH , The Netherlands
| | - P J M van Bentum
- Institute for Molecules and Materials (IMM) , Radboud University , Nijmegen 6525 AJ , The Netherlands
| | - A P M Kentgens
- Institute for Molecules and Materials (IMM) , Radboud University , Nijmegen 6525 AJ , The Netherlands
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Dumez JN. Perspectives on hyperpolarised solution-state magnetic resonance in chemistry. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:38-46. [PMID: 27495362 DOI: 10.1002/mrc.4496] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 07/28/2016] [Accepted: 08/01/2016] [Indexed: 06/06/2023]
Abstract
This perspective article reviews some of the recent developments in the field of hyperpolarisation, with a focus on solution-state NMR spectroscopy of small molecules. Two techniques are considered in more detail, dissolution dynamic nuclear polarisation (D-DNP) and signal amplification by reversible exchange (SABRE). Some of the opportunities and challenges for applications of hyperpolarised solution-state magnetic resonance in chemistry are discussed. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Jean-Nicolas Dumez
- Institut de Chimie des Substances Naturelles, CNRS UPR 2301, Univ. Paris-Sud, Université Paris-Saclay, Gif-sur-Yvette, France
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van Bentum J, van Meerten B, Sharma M, Kentgens A. Perspectives on DNP-enhanced NMR spectroscopy in solutions. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 264:59-67. [PMID: 26920831 DOI: 10.1016/j.jmr.2016.01.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 01/12/2016] [Accepted: 01/13/2016] [Indexed: 05/03/2023]
Abstract
More than 60 years after the seminal work of Albert Overhauser on dynamic nuclear polarization by dynamic cross relaxation of coupled electron-nuclear spin systems, the quest for sensitivity enhancement in NMR spectroscopy is as pressing as ever. In this contribution we will review the status and perspectives for dynamic nuclear polarization in the liquid state. An appealing approach seems to be the use of supercritical solvents that may allow an extension of the Overhauser mechanism towards common high magnetic fields. A complementary approach is the use of solid state DNP on frozen solutions, followed by a rapid dissolution or in-situ melting step and NMR detection with substantially enhanced polarization levels in the liquid state. We will review recent developments in the field and discuss perspectives for the near future.
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