scholarly journals Virtual decoupling to break the simplification versus resolution trade-off in nuclear magnetic resonance of complex metabolic mixtures

2021 ◽  
Vol 2 (2) ◽  
pp. 619-627
Author(s):  
Cyril Charlier ◽  
Neil Cox ◽  
Sophie Martine Prud'homme ◽  
Alain Geffard ◽  
Jean-Marc Nuzillard ◽  
...  
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Dreissena Polymorpha ◽  
Complex Mixture ◽  
Metabolite Identification ◽  
Proton Spectrum ◽  
Hsqc Spectrum ◽  
Trade Off ◽  
The One ◽  
Nuclear Magnetic

Abstract. The heteronuclear single quantum correlation (HSQC) experiment developed by Bodenhausen and Ruben (1980) in the early days of modern nuclear magnetic resonance (NMR) is without a doubt one of the most widely used experiments, with applications in almost every aspect of NMR including metabolomics. Acquiring this experiment, however, always implies a trade-off: simplification versus resolution. Here, we present a method that artificially lifts this barrier and demonstrate its application towards metabolite identification in a complex mixture. Based on the measurement of clean in-phase and clean anti-phase (CLIP/CLAP) HSQC spectra (Enthart et al., 2008), we construct a virtually decoupled HSQC (vd-HSQC) spectrum that maintains the highest possible resolution in the proton dimension. Combining this vd-HSQC spectrum with a J-resolved spectrum (Pell and Keeler, 2007) provides useful information for the one-dimensional proton spectrum assignment and for the identification of metabolites in Dreissena polymorpha (Prud'homme et al., 2020).

scholarly journals Virtual decoupling to break the Simplification Versus Resolution Trade Off in NMR of Complex Metabolic Mixtures

2021 ◽  
Author(s):  
Cyril Charlier ◽  
Neil Cox ◽  
Sophie Martine Prud'homme ◽  
Alain Geffard ◽  
Jean-Marc Nuzillard ◽  
...  
Keyword(s):  
Dreissena Polymorpha ◽  
Complex Mixture ◽  
Metabolite Identification ◽  
Proton Spectrum ◽  
Hsqc Spectrum ◽  
Trade Off ◽  
Spectrum Assignment ◽  
One Dimensional ◽  
The One

Abstract. The HSQC experiment developed by Bodenhausen and Ruben (Bodenhausen and Ruben, 1980) in the early days of modern NMR is without a doubt one of the most widely used experiments, with applications in almost every aspect of NMR including metabolomics. Acquiring this experiment however always implies a trade-off: simplification versus resolution. Here, we present a method that artificially lifts this barrier, and demonstrate its application towards metabolite identification in a complex mixture. Based on the measurement of CLean In-Phase and CLean Anti-Phase (CLIP/CLAP) HSQC spectra (Enthart et al., 2008), we construct a virtually decoupled HSQC (vd-HSQC) spectrum that maintains the highest possible resolution in the proton dimension. Combining this vd-HSQC spectrum with a J-resolved spectrum (Pell and Keeler, 2007) provides useful information for the one-dimensional proton spectrum assignment and for the identification of metabolites in Dreissena polymorpha (Prud’homme et al., 2020).

1H nuclear magnetic resonance and molecular orbital estimates of the internal rotational barrier in phenylpropynal in solution and in the vapor

1992 ◽  
Vol 70 (9) ◽  
pp. 2365-2369 ◽  
Author(s):  
Ted Schaefer ◽  
Rudy Sebastian ◽  
Robert W. Schurko
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Molecular Orbital ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Basis Sets ◽  
Am1 Calculations ◽  
Internal Barrier ◽  
The One ◽  
Nuclear Magnetic

The 1H nuclear magnetic resonance spectra of phenylpropynal and 1-phenylpropyne are analyzed for CS2/C6D12 and acetone-d6 solutions. The ensuing spin–spin coupling constants over eight formal bonds are used in assessing the conformational dependence of the one in the propynal derivative, as compared to the one over six bonds in benzaldehyde. The eight-bond coupling constant in phenylpropynal implies, via a hindered rotor model, that the twofold barrier to internal rotation is 5.9 ± 1.6 kJ/mol in both solutions. This number is much smaller than that for the internal barrier in benzaldehyde, reflecting the reduced π electron conjugation in phenylpropynal. Molecular orbital computations, with geometry optimization, confirm the essentially purely twofold internal barrier in the free propynal. The theoretical magnitudes are given for AM1 calculations, as well as for abinitio computations with STO-3G, 3-21G, 6-31G, and 6-31G* bases. To within experimental error, the barrier magnitudes from the split-valence basis sets agree with those obtained in solution.

Nuclear magnetic resonance spectra of oriented 4-spin systems with C2v symmetry (AA′BB′). The spectrum of thiophene

1968 ◽  
Vol 46 (16) ◽  
pp. 2645-2648 ◽  
Author(s):  
P. Diehl ◽  
C. L. Khetrapal ◽  
U. Lienhard
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Nematic Phase ◽  
Spin Systems ◽  
Direct Coupling ◽  
Proton Spectrum ◽  
Nuclear Magnetic Resonance Spectra ◽  
Interproton Distances ◽  
Magnetic Resonance Spectra ◽  
Nuclear Magnetic

The general Hamiltonian for the nuclear magnetic resonance (n.m.r.) spectra of oriented 4-spin systems with C2v symmetry of the type (AA′BB′) is reported. The system can be discussed analytically, if only the direct coupling between the various nuclei is considered. The expressions for transition frequencies and intensities for such a case are given.The proton spectrum of thiophene in the nematic phase of p,p′-di-n-hexyloxyazoxybenzene has been analyzed. The ratios of the various interproton distances are determined.

scholarly journals Challenges in Identifying the Dark Molecules of Life

2019 ◽  
Vol 12 (1) ◽  
pp. 177-199 ◽  
Author(s):  
María Eugenia Monge ◽  
James N. Dodds ◽  
Erin S. Baker ◽  
Arthur S. Edison ◽  
Facundo M. Fernández
Keyword(s):  
Mass Spectrometry ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Big Data Analytics ◽  
Metabolite Identification ◽  
Resonance Spectroscopy ◽  
Technological Advances ◽  
Central Bottleneck ◽  
Living Organisms ◽  
Nuclear Magnetic

Metabolomics is the study of the metabolome, the collection of small molecules in living organisms, cells, tissues, and biofluids. Technological advances in mass spectrometry, liquid- and gas-phase separations, nuclear magnetic resonance spectroscopy, and big data analytics have now made it possible to study metabolism at an omics or systems level. The significance of this burgeoning scientific field cannot be overstated: It impacts disciplines ranging from biomedicine to plant science. Despite these advances, the central bottleneck in metabolomics remains the identification of key metabolites that play a class-discriminant role. Because metabolites do not follow a molecular alphabet as proteins and nucleic acids do, their identification is much more time consuming, with a high failure rate. In this review, we critically discuss the state-of-the-art in metabolite identification with specific applications in metabolomics and how technologies such as mass spectrometry, ion mobility, chromatography, and nuclear magnetic resonance currently contribute to this challenging task.

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