1
|
Wörtge D, Parziale M, Claussen J, Mohebbi B, Stapf S, Blümich B, Augustine M. Quantitative stray-field T 1 relaxometry with the matrix pencil method. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 351:107435. [PMID: 37060888 DOI: 10.1016/j.jmr.2023.107435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 03/17/2023] [Accepted: 04/01/2023] [Indexed: 05/29/2023]
Abstract
The matrix pencil method (MPM) is tested as an approach to quantitatively process multiexponential low-field nuclear magnetic resonance T1 relaxometry data. The data is obtained by measuring T1 saturation recovery curves in the highly inhomogeneous magnetic field of a stray-field sensor. 0.9% brine solutions, doped with different concentrations of a Gd3+ containing contrast agent, serve as test liquids. Relaxation-times as a function of contrast-agent concentration along with the T1 relaxation curves for combinations of multiple different test liquids are measured, and the results from processing using MPM as well as inverse Laplace transformation as a benchmark are compared. The relaxation-time resolution limits of both procedures are probed by gradually reducing the difference between the relaxation-times of two liquids measured simultaneously. The sensitivity to quantify the relative contribution of each component to the magnetization build-up curve is explored by changing their volume ratio. Furthermore, the potential to resolve systems with more than two components is tested. For the systems under test, MPM shows superior performance in separating two or three relaxation components, respectively and effectively quantifying the time constants.
Collapse
Affiliation(s)
- Dennis Wörtge
- Institut für Technische Physik, TU Ilmenau, PO Box 100 565, 98684 Ilmenau, Germany; P&G Service GmbH., German Inovation Center, Sulzacher Straße 40, 65824 Schwalbach am Taunus, Germany.
| | - Matthew Parziale
- Dept. of Chemistry, University of California Davis, 69 Chemistry Building, 95616 Davis, CA, USA
| | - Jan Claussen
- P&G Service GmbH., German Inovation Center, Sulzacher Straße 40, 65824 Schwalbach am Taunus, Germany
| | - Behzad Mohebbi
- P&G Service GmbH., German Inovation Center, Sulzacher Straße 40, 65824 Schwalbach am Taunus, Germany
| | - Siegfried Stapf
- Institut für Technische Physik, TU Ilmenau, PO Box 100 565, 98684 Ilmenau, Germany
| | - Bernhard Blümich
- Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Worringerweg 2, 52074 Aachen, Germany
| | - Matthew Augustine
- Dept. of Chemistry, University of California Davis, 69 Chemistry Building, 95616 Davis, CA, USA
| |
Collapse
|
2
|
Yamada S, Tsuboi Y, Yokoyama D, Kikuchi J. Polymer composition optimization approach based on feature extraction of bound and free water using time-domain nuclear magnetic resonance. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 351:107438. [PMID: 37084520 DOI: 10.1016/j.jmr.2023.107438] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 03/30/2023] [Accepted: 04/05/2023] [Indexed: 05/03/2023]
Abstract
As global environmental sustainability becomes increasingly emphasized, the development of eco-friendly materials, including solutions to the issue of marine plastics, is thriving. However, the material parameter space is vast, making efficient search a challenge. Time-domain nuclear magnetic resonance offers material property information through the complex T2 relaxation curves resulting from multiple mobilities. In this research, we used the Carr-Purcell-Meiboom-Gill (CPMG) pulse sequence to evaluate the binding state of water (water affinity) in polymers synthesized with various monomer compositions, which were immersed in seawater. We also assessed the T2 relaxation property of the polymers using the magic sandwich echo, double quantum filter, and magic-and-polarization echo filter techniques. We separated the T2 relaxation curves of CPMG into free and bound water for polymers by employing semisupervized nonnegative matrix factorization. By employing the features of separated bound water and polymer properties, a polymer composition optimization method offered crucial factors to monomers through random forests, predicted the components of the polymer using generative topography mapping regression, and determined expected values using Bayesian optimization for polymer composition candidates with the desired high water affinity and high rigidity.
Collapse
Affiliation(s)
- Shunji Yamada
- RIKEN Center for Sustainable Resource Science, 1-7-22, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Yuuri Tsuboi
- RIKEN Center for Sustainable Resource Science, 1-7-22, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Daiki Yokoyama
- RIKEN Center for Sustainable Resource Science, 1-7-22, Tsurumi-ku, Yokohama 230-0045, Japan
| | - Jun Kikuchi
- RIKEN Center for Sustainable Resource Science, 1-7-22, Tsurumi-ku, Yokohama 230-0045, Japan; Graduate School of Bioagricultural Sciences, Nagoya University, 1 Furo-cho, Chikusa-ku, Nagoya, Aichi 464-0810, Japan; Graduate School of Medical Life Science, Yokohama City University, 1-7-29 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa 230-0045, Japan.
| |
Collapse
|
3
|
Kharbanda Y, Mailhiot S, Mankinen O, Urbańczyk M, Telkki VV. Monitoring cheese ripening by single-sided nuclear magnetic resonance. J Dairy Sci 2023; 106:1586-1595. [PMID: 36710190 PMCID: PMC9947740 DOI: 10.3168/jds.2022-22458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 10/22/2022] [Indexed: 01/31/2023]
Abstract
The noninvasive, longitudinal study of products and food processing is of interest for the dairy industry. Here, we demonstrated that single-sided nuclear magnetic resonance (NMR) can be used for noninvasive monitoring of the cheese ripening process. The maturation of soft-ripened Camembert-like molded cheese samples was monitored for 20 d measuring 1-dimensional and 2-dimensional NMR relaxation and diffusion data at various depths, ranging from the hard surface layer to the soft center. Gelation and gel shrinkage were observed throughout ripening, and a complete loss of free water signal was observed at the cheese rind. Transversal (T2) relaxation distributions include 3 components that evolve with ripening time and position, corresponding to water inside the casein gel network, water trapped in casein, and fat. Two-dimensional T1-T2 relaxation experiments provided enhanced resolution of the 3 components, allowing quantification of the relative proportions of each phase. Furthermore, diffusion (D)-T2 relaxation correlation experiments revealed the bimodal size distribution of fat globules. The study demonstrated that single-sided NMR can provide spatially resolved signal intensity, relaxation, and diffusion parameters that reflect structural changes during the ripening process and can be exploited to understand and monitor the ripening of cheeses.
Collapse
Affiliation(s)
- Y. Kharbanda
- NMR Research Unit, University of Oulu, 90570 Oulu, Finland
| | - S. Mailhiot
- NMR Research Unit, University of Oulu, 90570 Oulu, Finland
| | - O. Mankinen
- NMR Research Unit, University of Oulu, 90570 Oulu, Finland
| | - M. Urbańczyk
- Institute of Physical Chemistry, Polish Academy of Sciences, 01-224 Warsaw, Poland,Corresponding authors
| | - V.-V. Telkki
- NMR Research Unit, University of Oulu, 90570 Oulu, Finland,Corresponding authors
| |
Collapse
|
4
|
Mishra R, Dumez JN. Theoretical analysis of flow effects in spatially encoded diffusion NMR. J Chem Phys 2023; 158:014204. [PMID: 36610961 DOI: 10.1063/5.0130125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The measurement of translational diffusion coefficients by nuclear magnetic resonance (NMR) spectroscopy is essential in a broad range of fields, including organic, inorganic, polymer, and supramolecular chemistry. It is also a powerful method for mixture analysis. Spatially encoded diffusion NMR (SPEN DNMR)" is a time efficient technique to collect diffusion NMR data, which is particularly relevant for the analysis of samples that evolve in time. In many cases, motion other than diffusion is present in NMR samples. This is, for example, the case of flow NMR experiments, such as in online reaction monitoring and in the presence of sample convection. Such motion is deleterious for the accuracy of DNMR experiments in general and for SPEN DNMR in particular. Limited theoretical understanding of flow effects in SPEN DNMR experiments is an obstacle for their broader experimental implementation. Here, we present a detailed theoretical analysis of flow effects in SPEN DNMR and of their compensation, throughout the relevant pulse sequences. This analysis is validated by comparison with numerical simulation performed with the Fokker-Planck formalism. We then consider, through numerical simulation, the specific cases of constant, laminar, and convection flow and the accuracy of SPEN DNMR experiments in these contexts. This analysis will be useful for the design and implementation of fast diffusion NMR experiments and for their applications.
Collapse
Affiliation(s)
- Rituraj Mishra
- CNRS, CEISAM, Nantes Université, UMR 6230, F-4400 Nantes, France
| | | |
Collapse
|
5
|
Ullah MS, Mankinen O, Zhivonitko VV, Telkki VV. Ultrafast transverse relaxation exchange NMR spectroscopy. Phys Chem Chem Phys 2022; 24:22109-22114. [PMID: 36074123 PMCID: PMC9491048 DOI: 10.1039/d2cp02944h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Molecular exchange between different physical or chemical environments occurs due to either diffusion or chemical transformation. Nuclear magnetic resonance (NMR) spectroscopy provides a means of understanding the molecular exchange in a noninvasive way and without tracers. Here, we introduce a novel two dimensional, single-scan ultrafast Laplace NMR (UF LNMR) method to monitor molecular exchange using transverse relaxation as a contrast. The UF T2–T2 relaxation exchange spectroscopy (REXSY) method shortens the experiment time by one to two orders of magnitude compared to its conventional counterpart. Contrary to the conventional EXSY, the exchanging sites are distinguished based on T2 relaxation times instead of chemical shifts, making the method especially useful for systems including physical exchange of molecules. Therefore, the UF REXSY method offers an efficient means for quantification of exchange processes in various fields such as cellular metabolism and ion transport in electrolytes. As a proof of principle, we studied a halogen-free orthoborate based ionic liquid system and followed molecular exchange between molecular aggregates and free molecules. The results are in good agreement with the conventional exchange studies. Due to the single-scan nature, the method potentially significantly facilitates the use of modern hyperpolarization techniques to boost the sensitivity by several orders of magnitude. An ultrafast two-dimensional NMR method allows quantification of molecular exchange rates efficiently based on T2 relaxation contrast.![]()
Collapse
Affiliation(s)
- Md Sharif Ullah
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Otto Mankinen
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Vladimir V Zhivonitko
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| | - Ville-Veikko Telkki
- NMR Research Unit, Faculty of Science, University of Oulu, P.O.Box 3000, 90014 Oulu, Finland.
| |
Collapse
|
6
|
Telkki VV, Urbańczyk M, Zhivonitko V. Ultrafast methods for relaxation and diffusion. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2021; 126-127:101-120. [PMID: 34852922 DOI: 10.1016/j.pnmrs.2021.07.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 07/07/2021] [Accepted: 07/08/2021] [Indexed: 06/13/2023]
Abstract
Relaxation and diffusion NMR measurements offer an approach to studying rotational and translational motion of molecules non-invasively, and they also provide chemical resolution complementary to NMR spectra. Multidimensional experiments enable the correlation of relaxation and diffusion parameters as well as the observation of molecular exchange phenomena through relaxation or diffusion contrast. This review describes how to accelerate multidimensional relaxation and diffusion measurements significantly through spatial encoding. This so-called ultrafast Laplace NMR approach shortens the experiment time to a fraction and makes even single-scan experiments possible. Single-scan experiments, in turn, significantly facilitate the use of nuclear spin hyperpolarization methods to boost sensitivity. The ultrafast Laplace NMR method is also applicable with low-field, mobile NMR instruments, and it can be exploited in many disciplines. For example, it has been used in studies of the dynamics of fluids in porous materials, identification of intra- and extracellular metabolites in cancer cells, and elucidation of aggregation phenomena in atmospheric surfactant solutions.
Collapse
Affiliation(s)
| | - Mateusz Urbańczyk
- NMR Research Unit, University of Oulu, P.O. Box 3000, FIN-90014, Finland; Centre of New Technologies, University of Warsaw, Banacha 2c, 02-097 Warsaw, Poland
| | | |
Collapse
|
7
|
Tickner BJ, Zhivonitko VV, Telkki VV. Ultrafast Laplace NMR to study metal-ligand interactions in reversible polarisation transfer from parahydrogen. Phys Chem Chem Phys 2021; 23:16542-16550. [PMID: 34338685 PMCID: PMC8359933 DOI: 10.1039/d1cp02383g] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Accepted: 07/22/2021] [Indexed: 12/11/2022]
Abstract
Laplace Nuclear Magnetic Resonance (NMR) can determine relaxation parameters and diffusion constants, giving valuable information about molecular structure and dynamics. Information about relaxation times (T1 and T2) and the self-diffusion coefficient (D) can be extracted from exponentially decaying NMR signals by performing a Laplace transform, which is a different approach to traditional NMR involving Fourier transform of a free induction decay. Ultrafast Laplace NMR uses spatial encoding to collect the entire data set in just a single scan which provides orders of magnitude time savings. In this work we use ultrafast Laplace NMR D-T2 correlation sequences to measure key relaxation (T2) and diffusion (D) parameters of methanolic solutions containing pyridine. For the first time we combine this technique with the hyperpolarisation technique Signal Amplification By Reversible Exchange (SABRE), which employs an iridium catalyst to reversibly transfer polarisation from parahydrogen, to boost the 1H NMR signals of pyridine by up to 300-fold. We demonstrate use of ultrafast Laplace NMR to monitor changes in pyridine T2 and D associated with ligation to the iridium SABRE catalyst and kinetic isotope exchange reactions. The combined 1440-fold reduction in experiment time and 300-fold 1H NMR signal enhancement allow the determination of pyridine D coefficients and T2 values at 25 mM concentrations in just 3 seconds using SABRE hyperpolarised ultrafast Laplace NMR.
Collapse
Affiliation(s)
- Ben. J. Tickner
- NMR Research Unit, Faculty of Science, University of Oulu90014Finland
| | | | | |
Collapse
|
8
|
Characterization of Water in Wood by Time-Domain Nuclear Magnetic Resonance Spectroscopy (TD-NMR): A Review. FORESTS 2021. [DOI: 10.3390/f12070886] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
This review summarizes the development of the experimental technique and analytical method for using TD-NMR to study wood-water interactions in recent years. We briefly introduce the general concept of TD-NMR and magnetic resonance imaging (MRI), and demonstrate their applications for characterizing the following aspects of wood-water interactions: water state, fiber saturation state, water distribution at the cellular scale, and water migration in wood. The aim of this review is to provide an overview of the utilizations and future research opportunities of TD-NMR in wood-water relations. It should be noted that this review does not cover the NMR methods that provide chemical resolution of wood macromolecules, such as solid-state NMR.
Collapse
|
9
|
Lin E, Telkki VV, Lin X, Huang C, Zhan H, Yang Y, Huang Y, Chen Z. High-Resolution Reconstruction for Multidimensional Laplace NMR. J Phys Chem Lett 2021; 12:5085-5090. [PMID: 34028285 PMCID: PMC8397344 DOI: 10.1021/acs.jpclett.1c01022] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Accepted: 05/19/2021] [Indexed: 06/12/2023]
Abstract
As a perfect complement to conventional NMR that aims for chemical structure elucidation, Laplace NMR constitutes a powerful technique to study spin relaxation and diffusion, revealing information on molecular motions and spin interactions. Different from conventional NMR adopting Fourier transform to deal with the acquired data, Laplace NMR relies on specially designed signal processing and reconstruction algorithms resembling the inverse Laplace transform, and it generally faces severe challenges in cases where high spectral resolution and high spectral dimensionality are required. Herein, based on the tensor technique for high-dimensional problems and the sparsity assumption, we propose a general method for high-resolution reconstruction of multidimensional Laplace NMR data. We show that the proposed method can reconstruct multidimensional Laplace NMR spectra in a high-resolution manner for exponentially decaying relaxation and diffusion data acquired by commercial NMR instruments. Therefore, it would broaden the scope of multidimensional Laplace NMR applications.
Collapse
Affiliation(s)
- Enping Lin
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Ville-Veikko Telkki
- NMR
Research Unit, University of Oulu, P.O. Box 3000, Oulu FIN-90014, Finland
| | - Xiaoqing Lin
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Chengda Huang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Haolin Zhan
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yu Yang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Yuqing Huang
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| | - Zhong Chen
- State
Key Laboratory of Physical Chemistry of Solid Surfaces, Xiamen University, Xiamen, Fujian 361005, China
| |
Collapse
|
10
|
Ullah MS, Zhivonitko VV, Samoylenko A, Zhyvolozhnyi A, Viitala S, Kankaanpää S, Komulainen S, Schröder L, Vainio SJ, Telkki VV. Identification of extracellular nanoparticle subsets by nuclear magnetic resonance. Chem Sci 2021; 12:8311-8319. [PMID: 34221312 PMCID: PMC8221169 DOI: 10.1039/d1sc01402a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/29/2021] [Indexed: 01/08/2023] Open
Abstract
Exosomes are a subset of secreted lipid envelope-encapsulated extracellular vesicles (EVs) of 50-150 nm diameter that can transfer cargo from donor to acceptor cells. In the current purification protocols of exosomes, many smaller and larger nanoparticles such as lipoproteins, exomers and microvesicles are typically co-isolated as well. Particle size distribution is one important characteristics of EV samples, as it reflects the cellular origin of EVs and the purity of the isolation. However, most of the physicochemical analytical methods today cannot illustrate the smallest exosomes and other small particles like the exomers. Here, we demonstrate that diffusion ordered spectroscopy (DOSY) nuclear magnetic resonance (NMR) method enables the determination of a very broad distribution of extracellular nanoparticles, ranging from 1 to 500 nm. The range covers sizes of all particles included in EV samples after isolation. The method is non-invasive, as it does not require any labelling or other chemical modification. We investigated EVs secreted from milk as well as embryonic kidney and renal carcinoma cells. Western blot analysis and immuno-electron microscopy confirmed expression of exosomal markers such as ALIX, TSG101, CD81, CD9, and CD63 in the EV samples. In addition to the larger particles observed by nanoparticle tracking analysis (NTA) in the range of 70-500 nm, the DOSY distributions include a significant number of smaller particles in the range of 10-70 nm, which are visible also in transmission electron microscopy images but invisible in NTA. Furthermore, we demonstrate that hyperpolarized chemical exchange saturation transfer (Hyper-CEST) with 129Xe NMR indicates also the existence of smaller and larger nanoparticles in the EV samples, providing also additional support for DOSY results. The method implies also that the Xe exchange is significantly faster in the EV pool than in the lipoprotein/exomer pool.
Collapse
Affiliation(s)
| | | | - Anatoliy Samoylenko
- Laboratory of Developmental Biology, Infotech Oulu, Oulu Center for Cell-Matrix Research, Kvantum Institute, Faculty of Biochemistry and Molecular Medicine Oulu Finland
| | - Artem Zhyvolozhnyi
- Laboratory of Developmental Biology, Infotech Oulu, Oulu Center for Cell-Matrix Research, Kvantum Institute, Faculty of Biochemistry and Molecular Medicine Oulu Finland
| | - Sirja Viitala
- Production Systems, Natural Resources Institute Finland (Luke) Jokioinen Finland
| | - Santeri Kankaanpää
- Production Systems, Natural Resources Institute Finland (Luke) Jokioinen Finland
| | | | - Leif Schröder
- Molecular Imaging, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP) Berlin Germany
- Division of Translational Molecular Imaging, German Cancer Research Center (DKFZ) Heidelberg Germany
| | - Seppo J Vainio
- Laboratory of Developmental Biology, Infotech Oulu, Oulu Center for Cell-Matrix Research, Kvantum Institute, Faculty of Biochemistry and Molecular Medicine Oulu Finland
| | | |
Collapse
|
11
|
|
12
|
Urbańczyk M, Kharbanda Y, Mankinen O, Telkki VV. Accelerating Restricted Diffusion NMR Studies with Time-Resolved and Ultrafast Methods. Anal Chem 2020; 92:9948-9955. [PMID: 32551510 PMCID: PMC7439255 DOI: 10.1021/acs.analchem.0c01523] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Restricted
diffusion of fluids in porous materials can be studied
by pulsed field gradient nuclear magnetic resonance (NMR) non-invasively
and without tracers. If the experiment is repeated many times with
varying diffusion delays, detailed information about pore sizes and
tortuosity can be recorded. However, the measurements are very time-consuming
because numerous repetitions are needed for gradient ramping and varying
diffusion delays. In this paper, we demonstrate two different strategies
for acceleration of the restricted diffusion NMR measurements: time-resolved
diffusion NMR and ultrafast Laplace NMR. The former is based on time-resolved
non-uniform sampling, while the latter relies on spatial encoding
of two-dimensional data. Both techniques allow similar 1–2
order of magnitude acceleration of acquisition, but they have different
strengths and weaknesses, which we discuss in detail. The feasibility
of the methods was proven by investigating restricted diffusion of
water inside tracheid cells of thermally modified pine wood.
Collapse
Affiliation(s)
| | | | - Otto Mankinen
- NMR Research Unit, University of Oulu, 90014 Oulu, Finland.,Oulu Functional NeuroImaging Group, Research Unit of Medical Imaging, Physics and Technology, Medical Research Center Oulu, University of Oulu and Oulu University Hospital, 90029 Oulu, Finland
| | | |
Collapse
|
13
|
Kharbanda Y, Urbańczyk M, Laitinen O, Kling K, Pallaspuro S, Komulainen S, Liimatainen H, Telkki VV. Comprehensive NMR Analysis of Pore Structures in Superabsorbing Cellulose Nanofiber Aerogels. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2019; 123:30986-30995. [PMID: 31983933 PMCID: PMC6977143 DOI: 10.1021/acs.jpcc.9b08339] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 11/28/2019] [Indexed: 06/10/2023]
Abstract
Highly porous cellulose nanofiber (CNF) aerogels are promising, environmentally friendly, reusable, and low-cost materials for several advanced environmental, biomedical, and electronic applications. The aerogels have a complex and hierarchical 3D porous network structure with pore sizes ranging from nanometers to hundreds of micrometers. The morphology of the network has a critical role on the performance of aerogels, but it is difficult to characterize thoroughly with traditional techniques. Here, we introduce a combination of nuclear magnetic resonance (NMR) spectroscopy techniques for comprehensive characterization of pore sizes and connectivity in the CNF aerogels. Cyclohexane absorbed in the aerogels was used as a probe fluid. NMR cryoporometry enabled us to characterize the size distribution of nanometer scale pores in between the cellulose nanofibers in the solid matrix of the aerogels. Restricted diffusion of cyclohexane revealed the size distribution of the dominant micrometer scale pores as well as the tortuosity of the pore network. T 2 relaxation filtered microscopic magnetic resonance imaging (MRI) method allowed us to determine the size distribution of the largest, submillimeter scale pores. The NMR techniques are nondestructive, and they provide information about the whole sample volume (not only surfaces). Furthermore, they show how absorbed liquids experience the complex 3D pore structure. Thorough characterization of porous structures is important for understanding the properties of the aerogels and optimizing them for various applications. The introduced comprehensive NMR analysis set is widely usable for a broad range of different kinds of aerogels used in different applications, such as catalysis, batteries, supercapacitors, hydrogen storage, etc.
Collapse
Affiliation(s)
| | | | - Ossi Laitinen
- Fibre
and Particle Engineering Research Unit, University of Oulu, 90014 Oulu, Finland
| | - Kirsten Kling
- National
Centre for Nano Fabrication and Characterization, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Sakari Pallaspuro
- Materials
and Mechanical Engineering, Centre for Advanced Steels Research (CASR), University of Oulu, 90014 Oulu, Finland
| | | | - Henrikki Liimatainen
- Fibre
and Particle Engineering Research Unit, University of Oulu, 90014 Oulu, Finland
| | | |
Collapse
|
14
|
Zhivonitko VV, Ullah MS, Telkki VV. Nonlinear sampling in ultrafast Laplace NMR. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 307:106571. [PMID: 31445478 DOI: 10.1016/j.jmr.2019.106571] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/25/2019] [Revised: 08/09/2019] [Accepted: 08/09/2019] [Indexed: 06/10/2023]
Abstract
Ultrafast Laplace NMR (UF-LNMR) reduces the experiment time of multidimensional relaxation and diffusion measurements to a fraction. Here, we demonstrate a method for nonlinear (in this case logarithmic) sampling of the indirect dimension in UF-LNMR measurements. The method is based on the use of frequency-swept pulses with the frequency nonlinearly increasing with time. This leads to an optimized detection of exponential experimental data and significantly improved resolution of LNMR parameters.
Collapse
Affiliation(s)
| | - Md Sharif Ullah
- NMR Research Unit, University of Oulu, P.O. Box 3000, 90014 Oulu, Finland
| | | |
Collapse
|
15
|
Nikitin K, O'Gara R. Mechanisms and Beyond: Elucidation of Fluxional Dynamics by Exchange NMR Spectroscopy. Chemistry 2019; 25:4551-4589. [PMID: 30421834 DOI: 10.1002/chem.201804123] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2018] [Indexed: 12/31/2022]
Abstract
Detailed mechanistic information is crucial to our understanding of reaction pathways and selectivity. Dynamic exchange NMR techniques, in particular 2D exchange spectroscopy (EXSY) and its modifications, provide indispensable intricate information on the mechanisms of organic and inorganic reactions and other phenomena, for example, the dynamics of interfacial processes. In this Review, key results from exchange NMR studies of small molecules over the last few decades are systemised and discussed. After a brief introduction to the theory, the key types of dynamic processes are identified and fundamental examples given of intra- and intermolecular reactions, which, in turn, could involve, or not, bond-making and bond-breaking events. Following that logic, internal molecular rotation, intramolecular stereomutation and molecular recognition will first be considered because they do not typically involve bond breaking. Then, rearrangements, substitution-type reactions, cyclisations, additions and other processes affecting chemical bonds will be discussed. Finally, interfacial molecular dynamics and unexpected combinations of different types of fluxional processes will also be highlighted. How exchange NMR spectroscopy helps to identify conformational changes, coordination and molecular recognition processes as well as quantify reaction energy barriers and extract detailed mechanistic information by using reaction rate theory in conjunction with computational techniques will be shown.
Collapse
Affiliation(s)
- Kirill Nikitin
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| | - Ryan O'Gara
- School of Chemistry, University College Dublin, Belfield, Dublin, Ireland
| |
Collapse
|