1
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Tatman BP, Franks WT, Brown SP, Lewandowski JR. Nuclear spin diffusion under fast magic-angle spinning in solid-state NMR. J Chem Phys 2023; 158:2890210. [PMID: 37171196 DOI: 10.1063/5.0142201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2023] [Accepted: 04/10/2023] [Indexed: 05/13/2023] Open
Abstract
Solid-state nuclear spin diffusion is the coherent and reversible process through which spin order is transferred via dipolar couplings. With the recent increases in magic-angle spinning (MAS) frequencies and magnetic fields becoming routinely applied in solid-state nuclear magnetic resonance, understanding how the increased 1H resolution obtained affects spin diffusion is necessary for interpretation of several common experiments. To investigate the coherent contributions to spin diffusion with fast MAS, we have developed a low-order correlation in Liouville space model based on the work of Dumez et al. (J. Chem. Phys. 33, 224501, 2010). Specifically, we introduce a new method for basis set selection, which accounts for the resonance-offset dependence at fast MAS. Furthermore, we consider the necessity of including chemical shift, both isotropic and anisotropic, in the modeling of spin diffusion. Using this model, we explore how different experimental factors change the nature of spin diffusion. Then, we show case studies to exemplify the issues that arise in using spin diffusion techniques at fast spinning. We show that the efficiency of polarization transfer via spin diffusion occurring within a deuterated and 100% back-exchanged protein sample at 60 kHz MAS is almost entirely dependent on resonance offset. We additionally identify temperature-dependent magnetization transfer in beta-aspartyl L-alanine, which could be explained by the influence of an incoherent relaxation-based nuclear Overhauser effect.
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Affiliation(s)
- Ben P Tatman
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - W Trent Franks
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Steven P Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Józef R Lewandowski
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, United Kingdom
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2
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Nishiyama Y, Hou G, Agarwal V, Su Y, Ramamoorthy A. Ultrafast Magic Angle Spinning Solid-State NMR Spectroscopy: Advances in Methodology and Applications. Chem Rev 2023; 123:918-988. [PMID: 36542732 PMCID: PMC10319395 DOI: 10.1021/acs.chemrev.2c00197] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Solid-state NMR spectroscopy is one of the most commonly used techniques to study the atomic-resolution structure and dynamics of various chemical, biological, material, and pharmaceutical systems spanning multiple forms, including crystalline, liquid crystalline, fibrous, and amorphous states. Despite the unique advantages of solid-state NMR spectroscopy, its poor spectral resolution and sensitivity have severely limited the scope of this technique. Fortunately, the recent developments in probe technology that mechanically rotate the sample fast (100 kHz and above) to obtain "solution-like" NMR spectra of solids with higher resolution and sensitivity have opened numerous avenues for the development of novel NMR techniques and their applications to study a plethora of solids including globular and membrane-associated proteins, self-assembled protein aggregates such as amyloid fibers, RNA, viral assemblies, polymorphic pharmaceuticals, metal-organic framework, bone materials, and inorganic materials. While the ultrafast-MAS continues to be developed, the minute sample quantity and radio frequency requirements, shorter recycle delays enabling fast data acquisition, the feasibility of employing proton detection, enhancement in proton spectral resolution and polarization transfer efficiency, and high sensitivity per unit sample are some of the remarkable benefits of the ultrafast-MAS technology as demonstrated by the reported studies in the literature. Although the very low sample volume and very high RF power could be limitations for some of the systems, the advantages have spurred solid-state NMR investigation into increasingly complex biological and material systems. As ultrafast-MAS NMR techniques are increasingly used in multidisciplinary research areas, further development of instrumentation, probes, and advanced methods are pursued in parallel to overcome the limitations and challenges for widespread applications. This review article is focused on providing timely comprehensive coverage of the major developments on instrumentation, theory, techniques, applications, limitations, and future scope of ultrafast-MAS technology.
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Affiliation(s)
- Yusuke Nishiyama
- JEOL Ltd., Akishima, Tokyo196-8558, Japan
- RIKEN-JEOL Collaboration Center, Yokohama, Kanagawa230-0045, Japan
| | - Guangjin Hou
- State Key Laboratory of Catalysis, Dalian National Laboratory for Clean Energy, 2011-Collaborative Innovation Center of Chemistry for Energy Materials, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian116023, China
| | - Vipin Agarwal
- Tata Institute of Fundamental Research, Sy. No. 36/P, Gopanpally, Hyderabad500 046, India
| | - Yongchao Su
- Analytical Research and Development, Merck & Co., Inc., Rahway, New Jersey07065, United States
| | - Ayyalusamy Ramamoorthy
- Biophysics, Department of Chemistry, Biomedical Engineering, Macromolecular Science and Engineering, Michigan Neuroscience Institute, University of Michigan, Ann Arbor, Michigan41809-1055, United States
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3
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Koprivica D, Martinho RP, Novakovic M, Jaroszewicz MJ, Frydman L. A denoising method for multidimensional magnetic resonance spectroscopy and imaging based on compressed sensing. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 338:107187. [PMID: 35292421 DOI: 10.1016/j.jmr.2022.107187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Revised: 02/27/2022] [Accepted: 03/01/2022] [Indexed: 06/14/2023]
Abstract
Both in spectroscopy and imaging, t1-noise arising from instabilities such as temperature alterations, field-related frequency drifts, electronic and sample-spinning instabilities, or motions in in vivo experiments, affects many 2D Magnetic Resonance experiments. This work introduces a post-processing method that aims to attenuate t1-noise, by suitably averaging multiple signals/representations that have been reconstructed from the sampled data. The ensuing Compressed Sensing Multiplicative (CoSeM) denoising starts from a fully sampled 2D MR data set, discards random indirect-domain points, and makes up for these missing, masked data, by a compressed sensing reconstruction of the now incompletely sampled 2D data set. This procedure is repeated for multiple renditions of the masked data -some of which will have been more strongly affected by t1-noise than others. This leads to a large set of 2D NMR spectra/images compatible with the collected data; CoSeM chooses out of these those renditions that reduce the noise according to a suitable criterion, and then sums up their spectra/images leading to a reduction in t1-noise. The performance of the method was assessed in synthetic data, as well as in numerous different experiments: 2D solid and solution state NMR, 2D localized MRS of live brains, and 2D abdominal MRI. Throughout all these data, CoSeM processing evidenced 2-3 fold increases in SNR, without introducing biases, false peaks, or spectral/image blurring. CoSeM also retains a quantitative linearity in the information -allowing, for instance, reliable T1 inversion-recovery MRI mapping experiments.
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Affiliation(s)
- David Koprivica
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Ricardo P Martinho
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Mihajlo Novakovic
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Michael J Jaroszewicz
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
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4
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Tognetti J, Franks WT, Lewandowski JR, Brown SP. Optimisation of 1H PMLG homonuclear decoupling at 60 kHz MAS to enable 15N-1H through-bond heteronuclear correlation solid-state NMR spectroscopy. Phys Chem Chem Phys 2022; 24:20258-20273. [PMID: 35975627 PMCID: PMC9429863 DOI: 10.1039/d2cp01041k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The Lee–Goldburg condition for homonuclear decoupling in 1H magic-angle spinning (MAS) solid-state NMR sets the angle θ, corresponding to arctan of the ratio of the rf nutation frequency, ν1, to the rf offset, to be the magic angle, θm, equal to tan−1(√2) = 54.7°. At 60 kHz MAS, we report enhanced decoupling compared to MAS alone in a 1H spectrum of 15N-glycine with at θ = 30° for a ν1 of ∼100 kHz at a 1H Larmor frequency, ν0, of 500 MHz and 1 GHz, corresponding to a high chemical shift scaling factor (λCS) of 0.82. At 1 GHz, we also demonstrate enhanced decoupling compared to 60 kHz MAS alone for a lower ν1 of 51 kHz, i.e., a case where the nutation frequency is less than the MAS frequency, with θ = 18°, λCS = 0.92. The ratio of the rotor period to the decoupling cycle time, Ψ = τr/τc, is in the range 0.53 to 0.61. Windowed decoupling using the optimised parameters for a ν1 of ∼100 kHz also gives good performance in a 1H spin-echo experiment, enabling implementation in a 1H-detected 15N–1H cross polarisation (CP)-refocused INEPT heteronuclear correlation NMR experiment. Specifically, initial 15N transverse magnetisation as generated by 1H–15N CP is transferred back to 1H using a refocused INEPT pulse sequence employing windowed 1H decoupling. Such an approach ensures the observation of through-bond N–H connectivities. For 15N-glycine, while the CP-refocused INEPT experiment has a lower sensitivity (∼50%) as compared to a double CP experiment (with a 200 μs 15N to 1H CP contact time), there is selectivity for the directly bonded NH3+ moiety, while intensity is observed for the CH21H resonances in the double CP experiment. Two-dimensional 15N–1H correlation MAS NMR spectra are presented for the dipeptide β-AspAla and the pharmaceutical cimetidine at 60 kHz MAS, both at natural isotopic abundance. For the dipeptide β-AspAla, different build-up dependence on the first spin-echo duration is observed for the NH and NH3+ moieties demonstrating that the experiment could be used to distinguish resonances for different NHx groups. 15N–1H heteronuclear NMR correlation at natural abundance in the solid state via J couplings is enabled by optimisation of phase-modulated Lee–Goldburg (PMLG) 1H homonuclear decoupling during the spin echoes, far from the ideal magic-angle condition.![]()
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Affiliation(s)
- Jacqueline Tognetti
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
| | - W Trent Franks
- Department of Chemistry, University of Warwick, Coventry CV4 7AL, UK
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
| | | | - Steven P Brown
- Department of Physics, University of Warwick, Coventry CV4 7AL, UK.
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5
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Aleksis R, Pell AJ. Low-power synchronous helical pulse sequences for large anisotropic interactions in MAS NMR: Double-quantum excitation of 14N. J Chem Phys 2020; 153:244202. [PMID: 33380069 DOI: 10.1063/5.0030604] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
We develop a theoretical framework for a class of pulse sequences in the nuclear magnetic resonance (NMR) of rotating solids, which are applicable to nuclear spins with anisotropic interactions substantially larger than the spinning frequency, under conditions where the radiofrequency amplitude is smaller than or comparable to the spinning frequency. The treatment is based on average Hamiltonian theory and allows us to derive pulse sequences with well-defined relationships between the pulse parameters and spinning frequency for exciting specific coherences without the need for any detailed calculations. This framework is applied to the excitation of double-quantum spectra of 14N and is used both to evaluate the existing low-power pulse schemes and to predict the new ones, which we present here. It is shown that these sequences can be designed to be γ-encoded and therefore allow the acquisition of sideband-free spectra. It is also shown how these new double-quantum excitation sequences are incorporated into heteronuclear correlation NMR, such as 1H-14N dipolar double-quantum heteronuclear multiple-quantum correlation spectroscopy. The new experiments are evaluated both with numerical simulations and experiments on glycine and N-acetylvaline, which represent cases with "moderate" and "large" quadrupolar interactions, respectively. The analyzed pulse sequences perform well for the case of a "moderate" quadrupolar interaction, however poorly with a "large" quadrupolar interaction, for which future work on pulse sequence development is necessary.
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Affiliation(s)
- Rihards Aleksis
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Andrew J Pell
- Department of Materials and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden
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6
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Wijesekara AV, Venkatesh A, Lampkin BJ, VanVeller B, Lubach JW, Nagapudi K, Hung I, Gor'kov PL, Gan Z, Rossini AJ. Fast Acquisition of Proton-Detected HETCOR Solid-State NMR Spectra of Quadrupolar Nuclei and Rapid Measurement of NH Bond Lengths by Frequency Selective HMQC and RESPDOR Pulse Sequences. Chemistry 2020; 26:7881-7888. [PMID: 32315472 DOI: 10.1002/chem.202000390] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 04/20/2020] [Indexed: 12/14/2022]
Abstract
Fast magic-angle spinning (MAS), frequency selective (FS) heteronuclear multiple quantum coherence (HMQC) experiments which function in an analogous manner to solution SOFAST HMQC NMR experiments, are demonstrated. Fast MAS enables efficient FS excitation of 1 H solid-state NMR signals. Selective excitation and observation preserves 1 H magnetization, leading to a significant shortening of the optimal inter-scan delay. Dipolar and scalar 1 H{14 N} FS HMQC solid-state NMR experiments routinely provide 4- to 9-fold reductions in experiment times as compared to conventional 1 H{14 N} HMQC solid-state NMR experiments. 1 H{14 N} FS resonance-echo saturation-pulse double-resonance (RESPDOR) allowed dipolar dephasing curves to be obtained in minutes, enabling the rapid determination of NH dipolar coupling constants and internuclear distances. 1 H{14 N} FS RESPDOR was used to assign multicomponent active pharmaceutical ingredients (APIs) as salts or cocrystals. FS HMQC also provided enhanced sensitivity for 1 H{17 O} and 1 H{35 Cl} HMQC experiments on 17 O-labeled Fmoc-alanine and histidine hydrochloride monohydrate, respectively. FS HMQC and FS RESPDOR experiments will provide access to valuable structural constraints from materials that are challenging to study due to unfavorable relaxation times or dilution of the nuclei of interest.
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Affiliation(s)
- Anuradha V Wijesekara
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA.,US DOE Ames Laboratory, Ames, IA, 50011, USA
| | - Amrit Venkatesh
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA.,US DOE Ames Laboratory, Ames, IA, 50011, USA
| | - Bryan J Lampkin
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | - Brett VanVeller
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA
| | | | | | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), Tallahassee, FL, 32310, USA
| | - Peter L Gor'kov
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), Tallahassee, FL, 32310, USA
| | - Zhehong Gan
- Center of Interdisciplinary Magnetic Resonance (CIMAR), National High Magnetic Field Laboratory (NHMFL), Tallahassee, FL, 32310, USA
| | - Aaron J Rossini
- Department of Chemistry, Iowa State University, Ames, IA, 50011, USA.,US DOE Ames Laboratory, Ames, IA, 50011, USA
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7
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Venkatesh A, Luan X, Perras FA, Hung I, Huang W, Rossini AJ. t1-Noise eliminated dipolar heteronuclear multiple-quantum coherence solid-state NMR spectroscopy. Phys Chem Chem Phys 2020; 22:20815-20828. [DOI: 10.1039/d0cp03511d] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
t1-Noise eliminated (TONE) heteronuclear multiple quantum correlation (HMQC) solid-state nuclear magnetic resonance pulse sequences improve the sensitivity of 2D 1H{X} heteronuclear correlation experiments with X = 17O, 25Mg, 27Al and 35Cl.
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Affiliation(s)
- Amrit Venkatesh
- Department of Chemistry
- Iowa State University
- Ames
- USA
- US DOE Ames Laboratory
| | - Xuechen Luan
- Department of Chemistry
- Iowa State University
- Ames
- USA
| | | | - Ivan Hung
- National High Magnetic Field Laboratory (NHMFL)
- Tallahassee
- USA
| | - Wenyu Huang
- Department of Chemistry
- Iowa State University
- Ames
- USA
- US DOE Ames Laboratory
| | - Aaron J. Rossini
- Department of Chemistry
- Iowa State University
- Ames
- USA
- US DOE Ames Laboratory
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8
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Song L, Wang J, Su X, Zhang X, Li C, Zhou X, Yang D, Jiang B, Liu M. REAL‐
t
1
, an Effective Approach for
t
1
‐Noise Suppression in NMR Spectroscopy Based on Resampling Algorithm. CHINESE J CHEM 2019. [DOI: 10.1002/cjoc.201900389] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Linhong Song
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences Wuhan Hubei 430071 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Jiannan Wang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences Wuhan Hubei 430071 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Xuncheng Su
- State Key Laboratory of Elemento‐Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering, College of Chemistry, Nankai University Tianjin 300071 China
| | - Xu Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences Wuhan Hubei 430071 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Conggang Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences Wuhan Hubei 430071 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Xin Zhou
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences Wuhan Hubei 430071 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Daiwen Yang
- Department of Biological SciencesNational University of Singapore 14 Science Drive 4 Singapore 117543 Singapore
| | - Bin Jiang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences Wuhan Hubei 430071 China
- University of Chinese Academy of Sciences Beijing 100049 China
| | - Maili Liu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan National Laboratory for Optoelectronics, National Center for Magnetic Resonance in Wuhan, Key Laboratory of Magnetic Resonance in Biological Systems, Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences Wuhan Hubei 430071 China
- University of Chinese Academy of Sciences Beijing 100049 China
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9
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Hirsh DA, Wijesekara AV, Carnahan SL, Hung I, Lubach JW, Nagapudi K, Rossini AJ. Rapid Characterization of Formulated Pharmaceuticals Using Fast MAS 1H Solid-State NMR Spectroscopy. Mol Pharm 2019; 16:3121-3132. [DOI: 10.1021/acs.molpharmaceut.9b00343] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- David A. Hirsh
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | | | - Scott L. Carnahan
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
| | - Ivan Hung
- Center of Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, 1800 East Paul Dirac Drive, Tallahassee, Florida 32310, United States
| | - Joseph W. Lubach
- Genentech Inc., South San Francisco, California 94080, United States
| | - Karthik Nagapudi
- Genentech Inc., South San Francisco, California 94080, United States
| | - Aaron J. Rossini
- Department of Chemistry, Iowa State University, Ames, Iowa 50011, United States
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10
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Perras FA, Pruski M. Reducing t 1 noise through rapid scanning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 298:31-34. [PMID: 30513456 DOI: 10.1016/j.jmr.2018.11.008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2018] [Revised: 11/21/2018] [Accepted: 11/26/2018] [Indexed: 06/09/2023]
Abstract
The so-called t1 noise, which arises due to random instabilities in the spectrometer hardware, remains the primary source of noise that limits the sensitivity of most 2D NMR experiments, particularly in the expanding group of solid-state NMR methods that utilize dipolar-recoupling. In this communication we revisit the relationship between the signal intensity and the t1 noise produced. It is shown that since the latter scales linearly with the signal strength, the use of a conventional relaxation delay of 1.3T1 may prove far from optimal. In cases where the fluctuations occur on a shorter timescale than the recycle delay, a considerably faster repetition rate should be used to maximize the time sensitivity in a 2D experiment than what is used to maximize the sensitivity in 1D. This is demonstrated with the acquisition of 1H{13C} Dipolar-mediated Heteronuclear Multiple-Quantum Correlation (D-HMQC) type spectra in which the sensitivity could be nearly doubled by choosing a very short relaxation delay corresponding to 0.2T1.
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Affiliation(s)
| | - Marek Pruski
- US DOE, Ames Laboratory, Ames, IA 50011, USA; Department of Chemistry, Iowa State University, Ames, IA 50011, USA.
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11
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12
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Hayashi S, Jimura K. Spin diffusion and 1H spin-lattice relaxation in Cs 2(HSO 4)(H 2PO 4) containing a small amount of ammonium ions. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 88:15-21. [PMID: 29126075 DOI: 10.1016/j.ssnmr.2017.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2017] [Revised: 10/23/2017] [Accepted: 10/24/2017] [Indexed: 06/07/2023]
Abstract
Inorganic solid acid salts with hydrogen bond networks frequently show very long spin-lattice relaxation times even for 1H because the hydrogen bonds suppress motions. In the present work, the 1H spin-lattice relaxation in Cs2(HSO4)(H2PO4) containing a small amount of ammonium ions were studied in detail by use of the effect of magic angle spinning (MAS) on the relaxation. The 1H spin-lattice relaxation times of the acid protons decrease with increase in the content of ammonium ions. Reorientation of the NH4 group fluctuates the dipole-dipole interaction and relaxes the ammonium protons as well as the acid protons. The 1H relaxation times of the acid protons are a little bit longer than those of the ammonium protons at the MAS rate of 8 kHz. The spinning at 50 kHz makes the relaxation times of the acid protons longer and those of the ammonium protons shorter. Spin diffusion between the acid and the ammonium protons averages partially the 1H relaxation of the acid and the ammonium protons at the MAS rate of 8 kHz. The spin diffusion is suppressed completely at the MAS rate of 50 kHz. Spin diffusion between the acid protons is not suppressed at the MAS rate of 50 kHz. The acid protons always show the same relaxation times. The intrinsic relaxation times not affected by spin diffusion are evaluated quantitatively for both the acid and the ammonium protons. Those values are independent of the ammonium content. Contribution of the spin diffusion between the acid and the ammonium protons to the relaxation is estimated quantitatively. Using those parameters, the effect of ammonium ions on the 1H spin-lattice relaxation can be predicted. The 1H spin-lattice relaxation is a sensitive tool to study the distribution of ammonium ions in solids.
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Affiliation(s)
- Shigenobu Hayashi
- Research Institute for Material and Chemical Measurement, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
| | - Keiko Jimura
- Research Institute for Material and Chemical Measurement, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan
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13
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Hayashi S, Jimura K. Detailed mechanisms of 1H spin-lattice relaxation in ammonium dihydrogen phosphate confirmed by magic angle spinning. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 87:24-28. [PMID: 28728051 DOI: 10.1016/j.ssnmr.2017.07.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 06/07/2023]
Abstract
Mechanisms of the 1H spin-lattice relaxation in NH4H2PO4 were studied in detail by use of the effect of magic angle spinning on the relaxation. The acid and the ammonium protons have different relaxation times at the spinning rates higher than 10 kHz due to suppression of spin diffusion between the two kinds of protons. The intrinsic relaxation times not affected by the spin diffusion and the spin-diffusion assisted relaxation times were evaluated separately, taking into consideration temperature dependence. Both mechanisms contribute to the 1H relaxation of the acid protons comparatively. The spin-diffusion assisted relaxation mechanism was suppressed to the level lower than the experimental errors at the spinning rate of 30 kHz.
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Affiliation(s)
- Shigenobu Hayashi
- Research Institute for Material and Chemical Measurement, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan.
| | - Keiko Jimura
- Research Institute for Material and Chemical Measurement, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
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14
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Shen M, Wegner S, Trébosc J, Hu B, Lafon O, Amoureux JP. Minimizing the t 1-noise when using an indirect 1H high-resolution detection of unlabeled samples. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2017; 87:111-116. [PMID: 28688541 DOI: 10.1016/j.ssnmr.2017.06.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2017] [Revised: 06/25/2017] [Accepted: 06/26/2017] [Indexed: 06/07/2023]
Abstract
The most utilized through-space correlation 1H-{X} methods with proton indirect detection use two consecutive transfers, 1H → X and then X → 1H, with the evolution time t1 in the middle. When the X isotope is not 100% naturally abundant (NA), only the signal of the protons close to these isotopes is modulated by the 1H-X dipolar interactions. This signal is theoretically disentangled with phase-cycling from the un-modulated one. However, this separation is never perfect and it may lead to t1-noise in case of isotopes with very small NA, such as 13C or even worse 15N. One way to reduce this t1-noise is to minimize, 'purge', during t1 the un-modulated 1H magnetization before trying to suppress it with phase-cycling. We analyze experimentally several sequences following the HORROR condition, which allow purging the 1H transverse magnetization. The comparison is made at three spinning speeds, including very fast ones for 1H resolution: 27.75, 55.5 and 111 kHz. We show (i) that the efficiency of this purging process increases with the spinning speed, and (ii) that the best recoupling sequences are the two simplest ones: XY and S1 = SR212. We then compare the S/N that can be achieved with the two most used 1H-{X} 2D methods, called D-HMQC and CP-CP. The only difference in between these two methods is that the transfers are done with either two π/2-pulses on X channel (D-HMQC), or two Cross-Polarization (CP) transfers (CP-CP). The first method, D-HMQC, is very robust and should be preferred when indirectly detecting nuclei with high NA. The second method, CP-CP, (i) requires experimental precautions to limit the t1-noise, and (ii) is difficult to use with quadrupolar nuclei because the two CP transfers are then not efficient nor robust. However, CP-CP is presently the best method to indirectly detect isotopes with small NA, such as 13C and 15N.
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Affiliation(s)
- M Shen
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, PR China
| | - S Wegner
- Bruker BioSpin GmbH, 4 Silberstreifen, 76287 Rheinstetten, Germany
| | - J Trébosc
- Univ. Lille, UMR 8181, UCCS: Unit of Catalysis and Chemistry of Solids, 59000 Lille, France
| | - B Hu
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Materials Science, East China Normal University, Shanghai 200062, PR China
| | - O Lafon
- Univ. Lille, UMR 8181, UCCS: Unit of Catalysis and Chemistry of Solids, 59000 Lille, France; Institut Universitaire de France, 1 Rue Descartes, 75231 Paris, France
| | - J P Amoureux
- Univ. Lille, UMR 8181, UCCS: Unit of Catalysis and Chemistry of Solids, 59000 Lille, France; Bruker France, 34 Rue de l'Industrie, 67166 Wissembourg, France.
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Mo H, Harwood JS, Yang D, Post CB. A simple method for NMR t 1 noise suppression. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 276:43-50. [PMID: 28103498 PMCID: PMC5336490 DOI: 10.1016/j.jmr.2016.12.014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 12/26/2016] [Accepted: 12/26/2016] [Indexed: 06/06/2023]
Abstract
t1 noise appears as random or semi-random spurious streaks along the indirect t1 (F1) dimension of a 2D or nD NMR spectrum. It can significantly downgrade spectral quality, especially for spectra with strong diagonal signals such as NOESY, because useful and weak cross-peaks can be easily buried under t1 noise. One of the significant contributing factors to t1 noise is unwanted and semi-random F2 signal modulation during t1 acquisition. As such, t1 noise from different acquisitions is unlikely to correlate with each other strongly. In the case of NOESY, co-addition of multiple spectra significantly reduces t1 noise compared with conventional acquisition with the same amount of total acquisition time and resolution.
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Affiliation(s)
- Huaping Mo
- Purdue Inter-Departmental NMR Facility (PINMRF), Purdue University, West Lafayette, IN 47907, USA; Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA.
| | - John S Harwood
- Purdue Inter-Departmental NMR Facility (PINMRF), Purdue University, West Lafayette, IN 47907, USA; Department of Chemistry, Purdue University, West Lafayette, IN 47907, USA
| | - Danzhou Yang
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
| | - Carol Beth Post
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA
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16
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Reddy GNM, Malon M, Marsh A, Nishiyama Y, Brown SP. Fast Magic-Angle Spinning Three-Dimensional NMR Experiment for Simultaneously Probing H—H and N—H Proximities in Solids. Anal Chem 2016; 88:11412-11419. [DOI: 10.1021/acs.analchem.6b01869] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
| | - Michal Malon
- JEOL RESONANCE Inc., Musashino, Akishima,
Tokyo 196-8558, Japan
- RIKEN CLST-JEOL Collaboration Centre, Yokohama, Kanagawa 230-0045, Japan
| | | | - Yusuke Nishiyama
- JEOL RESONANCE Inc., Musashino, Akishima,
Tokyo 196-8558, Japan
- RIKEN CLST-JEOL Collaboration Centre, Yokohama, Kanagawa 230-0045, Japan
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17
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Nishiyama Y. Fast magic-angle sample spinning solid-state NMR at 60-100kHz for natural abundance samples. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2016; 78:24-36. [PMID: 27400153 DOI: 10.1016/j.ssnmr.2016.06.002] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Revised: 06/07/2016] [Accepted: 06/08/2016] [Indexed: 06/06/2023]
Abstract
In spite of tremendous progress made in pulse sequence designs and sophisticated hardware developments, methods to improve sensitivity and resolution in solid-state NMR (ssNMR) are still emerging. The rate at which sample is spun at magic angle determines the extent to which sensitivity and resolution of NMR spectra are improved. To this end, the prime objective of this article is to give a comprehensive theoretical and experimental framework of fast magic angle spinning (MAS) technique. The engineering design of fast MAS rotors based on spinning rate, sample volume, and sensitivity is presented in detail. Besides, the benefits of fast MAS citing the recent progress in methodology, especially for natural abundance samples are also highlighted. The effect of the MAS rate on (1)H resolution, which is a key to the success of the (1)H inverse detection methods, is described by a simple mathematical factor named as the homogeneity factor k. A comparison between various (1)H inverse detection methods is also presented. Moreover, methods to reduce the number of spinning sidebands (SSBs) for the systems with huge anisotropies in combination with (1)H inverse detection at fast MAS are discussed.
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Affiliation(s)
- Yusuke Nishiyama
- RIKEN CLST-JEOL Collaboration Center, RIKEN, Yokohama, Kanagawa 230-0045, Japan; JEOL RESONANCE Inc., Musashino, Akishima, Tokyo 186-8558, Japan.
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