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Kim J, Liu M, Chen HY, Hilty C. Determination of Intermolecular Interactions Using Polarization Compensated Heteronuclear Overhauser Effect of Hyperpolarized Spins. Anal Chem 2015; 87:10982-7. [DOI: 10.1021/acs.analchem.5b02934] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jihyun Kim
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Mengxiao Liu
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Hsueh-Ying Chen
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
| | - Christian Hilty
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, United States
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Pagès G, Dvinskikh SV, Furó I. Suppressing magnetization exchange effects in stimulated-echo diffusion experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2013; 234:35-43. [PMID: 23838524 DOI: 10.1016/j.jmr.2013.06.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 05/29/2013] [Accepted: 06/02/2013] [Indexed: 06/02/2023]
Abstract
Exchange of nuclear magnetization between spin pools, either by chemical exchange or by cross-relaxation or both, has a significant influence on the signal attenuation in stimulated-echo-type pulsed field gradient experiments. Hence, in such cases the obtained molecular self-diffusion coefficients can carry a large systematic error. We propose a modified stimulated echo pulse sequence that contains T2-filters during the z-magnetization store period. We demonstrate, using a common theoretical description for chemical exchange and cross-relaxation, that these filters suppress the effects of exchange on the diffusional decay in that frequent case where one of the participating spin pools is immobile and exhibits a short T2. We demonstrate the performance of this experiment in an agarose/water gel. We posit that this new experiment has advantages over other approaches hitherto used, such as that consisting of measuring separately the magnetization exchange rate, if suitable by Goldman-Shen type experiments, and then correcting for exchange effects within the framework of a two-site exchange model. We also propose experiments based on selective decoupling and applicable in systems with no large T2 difference between the different spin pools.
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Affiliation(s)
- Guilhem Pagès
- Division of Applied Physical Chemistry, Department of Chemistry, KTH Royal Institute of Technology, 100 44 Stockholm, Sweden.
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Nordstierna L, Yushmanov PV, Furó I. Solute−Solvent Contact by Intermolecular Cross-Relaxation. 2. The Water−Micelle Interface and the Micellar Interior. J Phys Chem B 2006; 110:25775-81. [PMID: 17181220 DOI: 10.1021/jp0647885] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The intermolecular dipole-dipole cross-relaxation is measured between 19F nuclei of sodium perfluorooctanoate in micelles and 1H nuclei of the water solvent. The cross-relaxation rates for fluorines in the different moieties along the surfactant vary strongly by the resonance frequency in the investigated range of 188-470 MHz. This frequency dependence indicates that the cross-relaxation between water and amphiphilic aggregates is not controlled solely by the fast local water dynamics but significantly contributed to by the long-range translational diffusion of water. The cross-relaxation rates, analyzed in the framework of a model (Nordstierna, L.; Yushmanov, P. V.; Furó, I. J. Chem. Phys. 2006, 125, 074704), provide information about the dynamic retardation of water molecules by the micellar headgroup region and the location of the various moieties along the hydrophobic tail with respect to the water-micelle interface. Both intermolecular cross-relaxation and aggregation-induced 19F chemical shift changes indicate no direct water contact to fluorines except for those closest to the head group.
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Affiliation(s)
- Lars Nordstierna
- Division of Physical Chemistry and Industrial NMR Center, Department of Chemistry, Royal Institute of Technology, SE-10044 Stockholm, Sweden
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Nordstierna L, Yushmanov PV, Furó I. Solute-solvent contact by intermolecular cross relaxation. I. The nature of the water-hydrophobic interface. J Chem Phys 2006; 125:074704. [PMID: 16942361 DOI: 10.1063/1.2336199] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Intermolecular cross-relaxation rates between solute and solvent were measured by {1H} 19F nuclear magnetic resonance experiments in aqueous molecular solutions of ammonium perfluoro-octanoate and sodium trifluoroacetate. The experiments performed at three different magnetic fields provide frequency-dependent cross-relaxation rates which demonstrate clearly the lack of extreme narrowing for nuclear spin relaxation by diffusionally modulated intermolecular interactions. Supplemented by suitable intramolecular cross-relaxation, longitudinal relaxation, and self-diffusion data, the obtained cross-relaxation rates are evaluated within the framework of recent relaxation models and provide information about the hydrophobic hydration. In particular, water dynamics around the trifluoromethyl group in ammonium perfluoro-octanoate are more retarded than that in the smaller trifluoroacetate.
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Affiliation(s)
- Lars Nordstierna
- Division of Physical Chemistry and Industrial NMR Center, Department of Chemistry, Royal Institute of Technology, SE-10044 Stockholm, Sweden
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Yushmanov PV, Furó I, Stilbs P. Micellar kinetics of a fluorosurfactant through stopped-flow NMR. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2006; 22:2002-4. [PMID: 16489781 DOI: 10.1021/la0529660] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
19F NMR chemical shifts and transverse relaxation times T2 were measured as a function of time after quick stopped-flow dilution of aqueous solutions of sodium perfluorooctanoate (NaPFO) with water. Different initial concentrations of micellar solution and different proportions of mixing were tested. Previous stopped-flow studies by time-resolved small-angle X-ray scattering (TR-SAXS) detection indicated a slow (approximately 10 s) micellar relaxation kinetics in NaPFO solutions. In contrast, no evidence of any comparable slow (>100 ms) relaxation process was found in our NMR studies. Possible artifacts of stopped-flow experiments are discussed as well as differences between NMR and SAXS detection methods. Upper bounds on the relative weight of a slow relaxation process are given within existing kinetic theories of micellar dissolution.
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Affiliation(s)
- Pavel V Yushmanov
- Division of Physical Chemistry and Industrial NMR Centre, Department of Chemistry, Royal Institute of Technology, SE-10044 Stockholm, Sweden
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Abstract
Intermolecular (1)H[(19)F] and (1)H[(1)H] nuclear Overhauser effects have been used to explore interaction of solvent components with melittin dissolved in 50% hexafluoroacetone trihydrate (HFA)/water. Standard nuclear Overhauser effect experiments and an analysis of C(alpha)H proton chemical shifts confirm that the conformation of the peptide in this solvent is alpha-helical from residues Ala4 to Thr11 and from Leu13 to Arg24. The two helical regions are not collinear; the interhelix angle (144 +/- 20 degrees ) found in this work is near that observed in the solid state and previous NMR studies. Intermolecular NOEs arising from interactions between spins of the solvent and the solute indicate that both fluoroalcohol and water molecules are strongly enough bound to the peptide that solvent-solute complexes persist for > or =2 ns. Preferential interactions of HFA with many hydrophobic side chains of the peptide are apparent while water molecules appear to be localized near hydrophilic side chains. These results indicate that interactions of both HFA and water are qualitatively different from those present when the peptide is dissolved in 35% hexafluoro-2-propanol/water, a chemically similar helix-supporting solvent system.
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Affiliation(s)
- J T Gerig
- Department of Chemistry & Biochemistry, University of California, Santa Barbara, Santa Barbara, CA 93106, USA.
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Amato ME, Caponetti E, Martino DC, Pedone L. H and 19F NMR Investigation on Mixed Hydrocarbon−Fluorocarbon Micelles. J Phys Chem B 2003. [DOI: 10.1021/jp022697b] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- M. E. Amato
- Dipartimento di Chimica Fisica, Università di Palermo, Viale delle Scienze, I-90128 Palermo, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy
| | - E. Caponetti
- Dipartimento di Chimica Fisica, Università di Palermo, Viale delle Scienze, I-90128 Palermo, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy
| | - D. Chillura Martino
- Dipartimento di Chimica Fisica, Università di Palermo, Viale delle Scienze, I-90128 Palermo, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy
| | - L. Pedone
- Dipartimento di Chimica Fisica, Università di Palermo, Viale delle Scienze, I-90128 Palermo, Italy, and Dipartimento di Scienze Chimiche, Università di Catania, Viale A. Doria 6, I-95125 Catania, Italy
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Yuan HZ, Tan XL, Cheng GZ, Zhao S, Zhang L, Mao SZ, An JY, Yu JY, Du YR. Micellization of Sodium Decyl Naphthalene Sulfonate Studied by 1H NMR. J Phys Chem B 2003. [DOI: 10.1021/jp022185x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- H. Z. Yuan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - X. L. Tan
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - G. Z. Cheng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - S. Zhao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - L. Zhang
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - S. Z. Mao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - J. Y. An
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - J. Y. Yu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
| | - Y. R. Du
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Wuhan Institute of Physics and Mathematics, The Chinese Academy of Sciences, Wuhan 430071, China, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100101, China, and Department of Chemistry, Wuhan University, Wuhan 430072, China
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Dvinskikh SV, Furó I. Measurement of the principal values of the anisotropic diffusion tensor in an unoriented sample by exploiting the chemical shift anisotropy: (19)F PGSE NMR with homonuclear decoupling. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2001; 148:73-77. [PMID: 11133278 DOI: 10.1006/jmre.2000.2208] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
NMR methods (S. V. Dvinskikh et al., J. Magn. Reson. 142, 102-110 (2000) and S. V. Dvinskikh and I. Furó, J. Magn. Reson. 144, 142-149 (2000)) that combine PGSE with dipolar decoupling are extended to polycrystalline solids and unoriented liquid crystals. Decoupling suppresses dipolar dephasing not only during the gradient pulses but also under signal acquisition so that the detected spectral shape is dominated by the chemical shift tensor of the selected nucleus. The decay of the spectral intensity at different positions in the powder spectrum provides the diffusion coefficient in sample regions with their crystal axes oriented differently with respect to the direction of the field gradient. Hence, one can obtain the principal values of the diffusion tensor. The method is demonstrated by (19)F PGSE NMR with homonuclear decoupling in a lyotropic lamellar liquid crystal.
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Affiliation(s)
- S V Dvinskikh
- Division of Physical Chemistry, Royal Institute of Technology, Stockholm, SE-10044, Sweden
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Dvinskikh SV, Furo I. Cross-relaxation effects in stimulated-echo-type PGSE NMR experiments by bipolar and monopolar gradient pulses. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2000; 146:283-289. [PMID: 11001844 DOI: 10.1006/jmre.2000.2158] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Exchange of longitudinal spin polarization by dipolar cross relaxation between nonequivalent spins results in a modulation of the stimulated echo signal on increasing the encoding/decoding delays and in a multiexponential decay on increasing the diffusion time. These artifacts are suppressed by 180 degrees pulses inserted in the middle of the gradient encoding/decoding periods. The efficiency of the gradient encoding is preserved if bipolar gradient pulses are used instead of monopolar pulses. The behavior of the different pulse sequences is demonstrated by (19)F PGSE NMR experiments in a lyotropic liquid crystal in both isotropic micellar and oriented nematic phases. Copyright 2000 Academic Press.
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Affiliation(s)
- SV Dvinskikh
- Division of Physical Chemistry, Royal Institute of Technology, Stockholm, SE-10044, Sweden
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