1
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Al-Aasmi ZH, Shchukina A, Butts CP. Accelerating quantitative 13C NMR spectra using an EXtended ACquisition Time (EXACT) method. Chem Commun (Camb) 2022; 58:7781-7784. [PMID: 35731109 DOI: 10.1039/d2cc01768g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Accurate quantitative 13C NMR spectra can be accelerated by using EXACT (EXtended ACquisition Time) NMR methods which reduce Nuclear Overhauser Enhancement (NOE) during the FID. This allows 30-50% shorter experiment times to be used when achieving a given level of quantitative accuracy.
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Affiliation(s)
- Zahra H Al-Aasmi
- School of Chemistry, University of Bristol, Cantocks Close, Bristol, BS8 1TS, UK.
| | | | - Craig P Butts
- School of Chemistry, University of Bristol, Cantocks Close, Bristol, BS8 1TS, UK.
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2
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Ben-Tal Y, Boaler PJ, Dale HJA, Dooley RE, Fohn NA, Gao Y, García-Domínguez A, Grant KM, Hall AMR, Hayes HLD, Kucharski MM, Wei R, Lloyd-Jones GC. Mechanistic analysis by NMR spectroscopy: A users guide. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 129:28-106. [PMID: 35292133 DOI: 10.1016/j.pnmrs.2022.01.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/05/2022] [Accepted: 01/06/2022] [Indexed: 06/14/2023]
Abstract
A 'principles and practice' tutorial-style review of the application of solution-phase NMR in the analysis of the mechanisms of homogeneous organic and organometallic reactions and processes. This review of 345 references summarises why solution-phase NMR spectroscopy is uniquely effective in such studies, allowing non-destructive, quantitative analysis of a wide range of nuclei common to organic and organometallic reactions, providing exquisite structural detail, and using instrumentation that is routinely available in most chemistry research facilities. The review is in two parts. The first comprises an introduction to general techniques and equipment, and guidelines for their selection and application. Topics include practical aspects of the reaction itself, reaction monitoring techniques, NMR data acquisition and processing, analysis of temporal concentration data, NMR titrations, DOSY, and the use of isotopes. The second part comprises a series of 15 Case Studies, each selected to illustrate specific techniques and approaches discussed in the first part, including in situ NMR (1/2H, 10/11B, 13C, 15N, 19F, 29Si, 31P), kinetic and equilibrium isotope effects, isotope entrainment, isotope shifts, isotopes at natural abundance, scalar coupling, kinetic analysis (VTNA, RPKA, simulation, steady-state), stopped-flow NMR, flow NMR, rapid injection NMR, pure shift NMR, dynamic nuclear polarisation, 1H/19F DOSY NMR, and in situ illumination NMR.
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Affiliation(s)
- Yael Ben-Tal
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Patrick J Boaler
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Harvey J A Dale
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Ruth E Dooley
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom; Evotec (UK) Ltd, 114 Innovation Drive, Milton Park, Abingdon, Oxfordshire OX14 4RZ, United Kingdom
| | - Nicole A Fohn
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Yuan Gao
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Andrés García-Domínguez
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Katie M Grant
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Andrew M R Hall
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Hannah L D Hayes
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Maciej M Kucharski
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Ran Wei
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom
| | - Guy C Lloyd-Jones
- School of Chemistry, Joseph Black Building, David Brewster Road, Edinburgh, EH9 3FJ, United Kingdom.
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3
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Pietrzak M, Jopa S, Mames A, Urbańczyk M, Woźny M, Ratajczyk T. Recent Progress in Liquid State Electrochemistry Coupled with NMR Spectroscopy. ChemElectroChem 2021. [DOI: 10.1002/celc.202100724] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- Mariusz Pietrzak
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Sylwia Jopa
- Faculty of Chemistry University of Warsaw Pasteura 1 02-093 Warsaw Poland
| | - Adam Mames
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Mateusz Urbańczyk
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
- Centre of New Technologies University of Warsaw Banacha 2 C 02-097 Warsaw Poland
| | - Mateusz Woźny
- Institute of Organic Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | - Tomasz Ratajczyk
- Institute of Physical Chemistry Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
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4
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Kaup KK, Toom L, Truu L, Miller S, Puurand M, Tepp K, Käämbre T, Reile I. A line-broadening free real-time 31P pure shift NMR method for phosphometabolomic analysis. Analyst 2021; 146:5502-5507. [PMID: 34515713 DOI: 10.1039/d1an01198g] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Phosphometabolomics by 31P NMR can be challenging, since overlapping multiplets of homonuclear coupled phosphorus nuclei complicate spectral analysis. Pure shift NMR allows to simplify such spectra by collapsing multiplets into singlets, but most pure shift methods require substantially elongated measurement times or cause disturbing spectral line broadening. Herein, we combine established pure shift NMR and artefact suppression techniques to record 31P pure shift NMR spectra without penalties in measurement time or line width. Examples are demonstrated in resolution of a mixture of nucleotide triphosphates and a biological sample of 18O labelled ATP isotopomers.
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Affiliation(s)
- Karl Kristjan Kaup
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia. .,Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Lauri Toom
- Institute of Chemistry, University of Tartu, Ravila 14A, 50411 Tartu, Estonia
| | - Laura Truu
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | - Sten Miller
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | - Marju Puurand
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | - Kersti Tepp
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | - Tuuli Käämbre
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
| | - Indrek Reile
- National Institute of Chemical Physics and Biophysics, Akadeemia tee 23, Tallinn 12618, Estonia.
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5
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Roginkin MS, Ndukwe IE, Craft DL, Williamson RT, Reibarkh M, Martin GE, Rovnyak D. Developing nonuniform sampling strategies to improve sensitivity and resolution in 1,1-ADEQUATE experiments. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2020; 58:625-640. [PMID: 31912914 DOI: 10.1002/mrc.4995] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Revised: 12/10/2019] [Accepted: 12/11/2019] [Indexed: 06/10/2023]
Abstract
Nonuniform sampling (NUS) strategies are developed for acquiring highly resolved 1,1-ADEQUATE spectra, in both conventional and homodecoupled (HD) variants with improved sensitivity. Specifically, the quantile-directed and Poisson gap methods were critically compared for distributing the samples nonuniformly, and the quantile schedules were further optimized for weighting. Both maximum entropy and iterative soft thresholding spectral estimation algorithms were evaluated. All NUS approaches were robust when the degree of data reduction is moderate, on the order of a 50% reduction of sampling points. Further sampling reduction by NUS is facilitated by using weighted schedules designed by the quantile method, which also suppresses sampling noise well. Seed independence and the ability to specify the sample weighting in quantile scheduling are important in optimizing NUS for 1,1-ADEQUATE data acquisition. Using NUS yields an improvement in sensitivity, while also making longer evolution times accessible that would be difficult or impractical to attain by uniform sampling. Theoretical predictions for the sensitivity enhancements in these experiments are in the range of 5-20%; NUS is shown to disambiguate weak signals, reveal some n JCC correlations obscured by noise, and improve signal strength relative to uniform sampling in the same experimental time. This work presents sample schedule development for applying NUS to challenging experiments. The schedules developed here are made available for general use and should facilitate the broader utilization of ADEQUATE experiments (including 1,1-, 1,n-, and HD- variants) for challenging structure elucidation problems.
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Affiliation(s)
- Mark S Roginkin
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | - Ikenna E Ndukwe
- Merck Research Laboratories, Analytical Research and Development, Merck and Co., Inc., Kenilworth, NJ, USA
- Complex Carbohydrate Research Center, University of Georgia, Athens, GA, USA
| | - D Levi Craft
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
| | - R Thomas Williamson
- Merck Research Laboratories, Analytical Research and Development, Merck and Co., Inc., Kenilworth, NJ, USA
- Department of Chemistry, University of North Carolina at Wilmington, Wilmington, NC, USA
| | - Mikhail Reibarkh
- Merck Research Laboratories, Analytical Research and Development, Merck and Co., Inc., Kenilworth, NJ, USA
| | - Gary E Martin
- Merck Research Laboratories, Analytical Research and Development, Merck and Co., Inc., Kenilworth, NJ, USA
- Department of Chemistry & Biochemistry, Seton Hall University, South Orange, NJ, USA
| | - David Rovnyak
- Department of Chemistry, Bucknell University, Lewisburg, PA, USA
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6
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Enhancing Compression Level for More Efficient Compressed Sensing and Other Lessons from NMR Spectroscopy. SENSORS 2020; 20:s20051325. [PMID: 32121309 PMCID: PMC7085760 DOI: 10.3390/s20051325] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Revised: 02/21/2020] [Accepted: 02/25/2020] [Indexed: 12/15/2022]
Abstract
Modern nuclear magnetic resonance spectroscopy (NMR) is based on two- and higher-dimensional experiments that allow the solving of molecular structures, i.e., determine the relative positions of single atoms very precisely. However, rich chemical information comes at the price of long data acquisition times (up to several days). This problem can be alleviated by compressed sensing (CS)—a method that revolutionized many fields of technology. It is known that CS performs the most efficiently when measured objects feature a high level of compressibility, which in the case of NMR signal means that its frequency domain representation (spectrum) has a low number of significant points. However, many NMR spectroscopists are not aware of the fact that various well-known signal acquisition procedures enhance compressibility and thus should be used prior to CS reconstruction. In this study, we discuss such procedures and show to what extent they are complementary to CS approaches. We believe that the survey will be useful not only for NMR spectroscopists but also to inspire the broader signal processing community.
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7
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Mobli M, Miljenović TM. Framework for and evaluation of bursts in random sampling of multidimensional NMR experiments. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 300:103-113. [PMID: 30738271 DOI: 10.1016/j.jmr.2019.01.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Revised: 01/23/2019] [Accepted: 01/24/2019] [Indexed: 06/09/2023]
Abstract
The grouping of data in bursts, also referred to as clusters, spikes or clumps, is a common phenomenon in stochastic sampling. There have been several reports that suggest that in NMR, the presence of such bursts is beneficial to spectral reconstruction where data are sampled nonuniformly. In this work, we seek to define a mode of sampling that produces bursts of randomly distributed data in a controlled manner. An algorithm is described for achieving this where the burst length and its uniformity is controlled - we refer to this type of sampling mode as clustered sampling. Measures are introduced for assessing the "burstiness" of nonuniformly sampled data in multiple dimensions and properties of the point-spread-function of these schedules are assessed. The clustered sampling method is applied to samples drawn from an exponentially weighted distribution either distributed randomly or pseudo-randomly by use of a jittering algorithm. The results reveal that bursts introduce characteristic sampling artifacts that are shifted to low frequencies (red shifted), with respect to the signal frequency, and that they produce artifact-reduced regions at frequencies related to the burst length. This observation is contrary to that observed for sampling methods that seek to evenly distribute NUS data, such as jittered or Poisson sampling. Extensive evaluation of simulated data with comparable inherent sensitivity, reveals that at high sampling coverage (25% in 1D), the distribution of the data has little impact on common spectral quality measures. Application of the introduced clustered sampling method to an experimental 3D NOESY experiment showed results consistent with that found for the simulated 1D data. However, in the extremes of very sparse sampling, the results suggest that there may be some advantages associated with incorporation of bursts in nonuniform sampling. The tools and theory presented will serve as a starting point to further explore this novel mode of sampling in NMR.
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Affiliation(s)
- Mehdi Mobli
- Centre for Advanced Imaging, The University of Queensland, St. Lucia, QLD 4072, Australia.
| | - Tomas M Miljenović
- Centre for Advanced Imaging, The University of Queensland, St. Lucia, QLD 4072, Australia
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8
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Shchukina A, Kaźmierczak M, Kasprzak P, Davy M, Akien GR, Butts CP, Kazimierczuk K. Accelerated acquisition in pure-shift spectra based on prior knowledge from 1H NMR. Chem Commun (Camb) 2019; 55:9563-9566. [DOI: 10.1039/c9cc05222d] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Pure shift NMR with maximum performance by non-uniform sampling with prior knowledge.
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Affiliation(s)
| | | | - Paweł Kasprzak
- Centre of New Technologies
- University of Warsaw
- 02-097 Warsaw
- Poland
- Faculty of Physics
| | - Matthew Davy
- School of Chemistry
- University of Bristol
- Clifton
- UK
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9
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Dumez JN. Spatial encoding and spatial selection methods in high-resolution NMR spectroscopy. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:101-134. [PMID: 30527133 DOI: 10.1016/j.pnmrs.2018.08.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Revised: 08/01/2018] [Accepted: 08/01/2018] [Indexed: 06/09/2023]
Abstract
A family of high-resolution NMR methods share the common concept of acquiring in parallel different sub-experiments in different spatial regions of the NMR tube. These spatial encoding and spatial selection methods were for the most part introduced independently from each other and serve different purposes, but they share common ingredients, often derived from magnetic resonance imaging, and they all benefit from a greatly improved time-efficiency. This review article provides a description of several spatial encoding and spatial selection methods, including single-scan multidimensional experiments (ultrafast 2D NMR, DOSY, Z spectroscopy, inversion recovery and Laplace NMR), pure shift and selective refocusing experiments (including Zangger-Sterk decoupling, G-SERF and PSYCHE), a Z filter, and fast-pulsing slice-selective experiments. Some key elements for spatial parallelisation are introduced and when possible a common framework is used for the analysis of each method. Sensitivity considerations are discussed, and a selection of applications is analysed to illustrate which questions can be answered thanks to spatial encoding and spatial selection methods, and discuss the perspectives for future developments and applications.
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Affiliation(s)
- Jean-Nicolas Dumez
- Institut de Chimie des Substances Naturelles, CNRS UPR2301, Univ. Paris Sud, Université Paris-Saclay, Avenue de la Terrasse, 91190 Gif-sur-Yvette, France.
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10
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Aguilar JA, Kenwright AM. Compressed NMR: Combining compressive sampling and pure shift NMR techniques. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2018; 56:983-992. [PMID: 29278289 DOI: 10.1002/mrc.4705] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Revised: 12/08/2017] [Accepted: 12/13/2017] [Indexed: 06/07/2023]
Abstract
Historically, the resolution of multidimensional nuclear magnetic resonance (NMR) has been orders of magnitude lower than the intrinsic resolution that NMR spectrometers are capable of producing. The slowness of Nyquist sampling as well as the existence of signals as multiplets instead of singlets have been two of the main reasons for this underperformance. Fortunately, two compressive techniques have appeared that can overcome these limitations. Compressive sensing, also known as compressed sampling (CS), avoids the first limitation by exploiting the compressibility of typical NMR spectra, thus allowing sampling at sub-Nyquist rates, and pure shift techniques eliminate the second issue "compressing" multiplets into singlets. This paper explores the possibilities and challenges presented by this combination (compressed NMR). First, a description of the CS framework is given, followed by a description of the importance of combining it with the right pure shift experiment. Second, examples of compressed NMR spectra and how they can be combined with covariance methods will be shown.
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11
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Kiraly P, Nilsson M, Morris GA. Semi-real-time acquisition for fast pure shift NMR at maximum resolution. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 293:19-27. [PMID: 29802964 DOI: 10.1016/j.jmr.2018.05.012] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2018] [Revised: 05/15/2018] [Accepted: 05/18/2018] [Indexed: 06/08/2023]
Abstract
Homonuclear decoupling can give impressive improvements in spectral resolution when overlapping multiplet structures limit the interpretability of NMR spectra. General homodecoupling methods ("pure shift NMR") typically use either interferogram-style acquisition, which is slow but gives optimum resolution, or real-time acquisition, which is fast but gives broader lines. Here we describe an alternative data acquisition strategy that allows rapid acquisition without resolution loss, illustrating the method with band-selective homodecoupling experiments and demonstrating its advantages over competing methods.
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Affiliation(s)
- Peter Kiraly
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Mathias Nilsson
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK
| | - Gareth A Morris
- School of Chemistry, University of Manchester, Oxford Road, Manchester M13 9PL, UK.
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12
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Craft DL, Sonstrom RE, Rovnyak VG, Rovnyak D. Nonuniform sampling by quantiles. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 288:109-121. [PMID: 29453083 DOI: 10.1016/j.jmr.2018.01.014] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2017] [Revised: 01/24/2018] [Accepted: 01/24/2018] [Indexed: 06/08/2023]
Abstract
A flexible strategy for choosing samples nonuniformly from a Nyquist grid using the concept of statistical quantiles is presented for broad classes of NMR experimentation. Quantile-directed scheduling is intuitive and flexible for any weighting function, promotes reproducibility and seed independence, and is generalizable to multiple dimensions. In brief, weighting functions are divided into regions of equal probability, which define the samples to be acquired. Quantile scheduling therefore achieves close adherence to a probability distribution function, thereby minimizing gaps for any given degree of subsampling of the Nyquist grid. A characteristic of quantile scheduling is that one-dimensional, weighted NUS schedules are deterministic, however higher dimensional schedules are similar within a user-specified jittering parameter. To develop unweighted sampling, we investigated the minimum jitter needed to disrupt subharmonic tracts, and show that this criterion can be met in many cases by jittering within 25-50% of the subharmonic gap. For nD-NUS, three supplemental components to choosing samples by quantiles are proposed in this work: (i) forcing the corner samples to ensure sampling to specified maximum values in indirect evolution times, (ii) providing an option to triangular backfill sampling schedules to promote dense/uniform tracts at the beginning of signal evolution periods, and (iii) providing an option to force the edges of nD-NUS schedules to be identical to the 1D quantiles. Quantile-directed scheduling meets the diverse needs of current NUS experimentation, but can also be used for future NUS implementations such as off-grid NUS and more. A computer program implementing these principles (a.k.a. QSched) in 1D- and 2D-NUS is available under the general public license.
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Affiliation(s)
- D Levi Craft
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Reilly E Sonstrom
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States
| | - Virginia G Rovnyak
- University of Virginia School of Nursing, Charlottesville, VA 22908, United States
| | - David Rovnyak
- Department of Chemistry, Bucknell University, Lewisburg, PA 17837, United States.
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13
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Abstract
Recent technological advances in mass spectrometry and NMR spectroscopy have enabled new approaches for the rapid and insightful profiling of natural product mixtures. MALDI-MS with the provision of biosynthetic heavy-isotope-labeled precursors can be a powerful method by which to interrogate a natural product metabolome and to gain insight into its unique constituents; this is illustrated herein by the detection, isolation, and characterization of cryptomaldamide. MS/MS-based Molecular Networks, facilitated by the Global Natural Products Social (GNPS) platform, is rapidly changing the way in which we dereplicate known natural products in mixtures, find new analogues in desired structure classes, and identify fundamentally new chemical entities. This method can be linked to genomic information to assist in genome-driven natural products discovery and is illustrated here with the characterization of the columbamides. Similarly, algorithmic interpretation of NMR data is facilitating the automatic identification or classification of new natural products. We developed such a tool named the Small Molecule Accurate Recognition Technology (SMART), which employs a convolutional neural network to classify HSQC spectra of organic molecules using pattern recognition principles. The discovery and rapid classification of several new peptides from a marine cyanobacterium as members of the viequeamide class provides an example of its utility in natural products research. These three illustrations represent different methods by which to look at the external features of a chemical substance and derive valuable insights into its identity or, as described herein, the "face of a molecule".
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Affiliation(s)
- William H Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography and Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego , La Jolla, California 92093, United States
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14
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Ndukwe IE, Shchukina A, Zorin V, Cobas C, Kazimierczuk K, Butts CP. Enabling Fast Pseudo-2D NMR Spectral Acquisition for Broadband Homonuclear Decoupling: The EXACT NMR Approach. Chemphyschem 2017; 18:2081-2087. [DOI: 10.1002/cphc.201700474] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Ikenna E. Ndukwe
- Department of Chemistry; University of Bristol; Cantocks Close Bristol. BS8 1TS UK
- Department of Pure and Industrial Chemistry; Abia State University; Uturu PMB 2000. Abia State Nigeria
| | - Alexandra Shchukina
- Centre of New Technologies; University of Warsaw; Banacha 2C 02089 Warszawa Poland
- Institute for Spectroscopy; Russian Academy of Sciences; Fizicheskaya 5 142190, Moscow Troitsk Russia
| | - Vadim Zorin
- Mestrelab Research S.L.; Feliciano Barrera 9B-Bajo 15706 Santiago de Compostela Spain
| | - Carlos Cobas
- Mestrelab Research S.L.; Feliciano Barrera 9B-Bajo 15706 Santiago de Compostela Spain
| | | | - Craig P. Butts
- Department of Chemistry; University of Bristol; Cantocks Close Bristol. BS8 1TS UK
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15
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Castañar L. Pure shift 1 H NMR: what is next? MAGNETIC RESONANCE IN CHEMISTRY : MRC 2017; 55:47-53. [PMID: 27761957 DOI: 10.1002/mrc.4545] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 10/14/2016] [Accepted: 10/17/2016] [Indexed: 06/06/2023]
Abstract
Currently, pure shift nuclear magnetic resonance (NMR) is an area of high interest. The aim of this contribution is to describe briefly how this technique has evolved, where it is now and what could be the next challenges in the amazing adventure of the development and application of pure shift NMR experiments. Copyright © 2016 John Wiley & Sons, Ltd.
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Affiliation(s)
- Laura Castañar
- School of Chemistry, University of Manchester, Manchester, UK
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16
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Ndukwe IE, Shchukina A, Kazimierczuk K, Butts CP. Rapid and safe ASAP acquisition with EXACT NMR. Chem Commun (Camb) 2016; 52:12769-12772. [DOI: 10.1039/c6cc07140f] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
EXACT acquisition allows the fast and safer acquisition of ASAP 2D NMR experiments in just a few seconds.
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Affiliation(s)
- I. E. Ndukwe
- School of Chemistry
- University of Bristol
- Bristol
- UK
| | - A. Shchukina
- Centre of New Technologies
- University of Warsaw
- Warszawa
- Poland
- Institute for Spectroscopy
| | - K. Kazimierczuk
- Centre of New Technologies
- University of Warsaw
- Warszawa
- Poland
| | - C. P. Butts
- School of Chemistry
- University of Bristol
- Bristol
- UK
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