Magnetic Resonance in Chemistry最新文献

{"title":"Graphical exploration of 600- and 60-MHz proton NMR spectral datasets from ground roast coffee extracts","authors":"E. Kate Kemsley","doi":"10.1002/mrc.5373","DOIUrl":"10.1002/mrc.5373","url":null,"abstract":"<p>This article uses a variety of graphical and mathematical approaches to analyse 600- and 60-MHz (‘benchtop’) proton NMR spectra acquired from lipophilic and hydrophilic extracts of roasted coffee beans. The collection of 40 authenticated samples comprised various coffee species, cultivars and hybrids. The spectral datasets were analysed by a combination of metabolomics approaches, cross-correlation and whole spectrum methods, assisted by visualisation and mathematical techniques not conventionally employed to treat NMR data. A large amount of information content was shared between the 600-MHz and benchtop datasets, including in its magnitude spectral form, suggesting the potential for a lower cost, lower tech route to conducting informative metabolomics studies.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5373","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9982944","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated identification and quantification of metabolites in human fecal extracts by nuclear magnetic resonance spectroscopy","authors":"Brian L. Lee,&nbsp;Manoj Rout,&nbsp;Rupasri Mandal,&nbsp;David S. Wishart","doi":"10.1002/mrc.5372","DOIUrl":"10.1002/mrc.5372","url":null,"abstract":"<p>We report the development of a software program, called MagMet-F, that automates the processing and quantification of 1D ¹H NMR of human fecal extracts. To optimize the program, we identified 82 potential fecal metabolites using 1D ¹H NMR of six human fecal extracts using manual profiling and a literature review of known fecal metabolites. We acquired pure versions of those metabolites and then acquired their 1D ¹H NMR spectra at 700 MHz to generate a fecal metabolite spectral library for MagMet-F. The fitting of these metabolites by MagMet-F was iteratively optimized to replicate manual profiling. We validated MagMet-F's automated profiling using a test set of six fecal extracts. It correctly identified 80% of the compounds and quantified those within &lt;20% of the values determined by manual profiling using Chenomx. We also compared MagMet-F's profiling performance to two other open-access NMR profiling tools, Bayesil and Batman. MagMet-F outperformed both. Bayesil repeatedly overestimated metabolite concentrations by 10% to 40% while Batman was unable to properly quantify any compounds and took 10–20× longer. We have implemented MagMet-F as a freely accessible web server to enable automated, fast and convenient 1D ¹H NMR spectral profiling of fecal samples. MagMet-F is available at https://www.magmet.ca.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5372","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9561720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MagMet: A fully automated web server for targeted nuclear magnetic resonance metabolomics of plasma and serum","authors":"Manoj Rout,&nbsp;Matthias Lipfert,&nbsp;Brian L. Lee,&nbsp;Mark Berjanskii,&nbsp;Nazanin Assempour,&nbsp;Rosa Vazquez Fresno,&nbsp;Arnau Serra Cayuela,&nbsp;Ying Dong,&nbsp;Mathew Johnson,&nbsp;Honeya Shahin,&nbsp;Vasuk Gautam,&nbsp;Tanvir Sajed,&nbsp;Eponine Oler,&nbsp;Harrison Peters,&nbsp;Rupasri Mandal,&nbsp;David S. Wishart","doi":"10.1002/mrc.5371","DOIUrl":"10.1002/mrc.5371","url":null,"abstract":"<p>Nuclear magnetic resonance (NMR) spectral analysis of biofluids can be a time-consuming process, requiring the expertise of a trained operator. With NMR becoming increasingly popular in the field of metabolomics, there is a growing need to change this paradigm and to automate the process. Here we introduce MagMet, an online web server, that automates the processing and quantification of 1D ¹H NMR spectra from biofluids—specifically, human serum/plasma metabolites, including those associated with inborn errors of metabolism (IEM). MagMet uses a highly efficient data processing procedure that performs automatic Fourier Transformation, phase correction, baseline optimization, chemical shift referencing, water signal removal, and peak picking/peak alignment. MagMet then uses the peak positions, linewidth information, and J-couplings from its own specially prepared standard metabolite reference spectral NMR library of 85 serum/plasma compounds to identify and quantify compounds from experimentally acquired NMR spectra of serum/plasma. MagMet employs linewidth adjustment for more consistent quantification of metabolites from higher field instruments and incorporates a highly efficient data processing procedure for more rapid and accurate detection and quantification of metabolites. This optimized algorithm allows the MagMet webserver to quickly detect and quantify 58 serum/plasma metabolites in 2.6 min per spectrum (when processing a dataset of 50–100 spectra). MagMet's performance was also assessed using spectra collected from defined mixtures (simulating other biofluids), with &gt;100 previously measured plasma spectra, and from spiked serum/plasma samples simulating known IEMs. In all cases, MagMet performed with precision and accuracy matching the performance of human spectral profiling experts. MagMet is available at http://magmet.ca.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5371","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9561723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the interaction between merocyanine and glutathione through a comprehensive NMR analysis of three GSH-stabilized merocyanine species","authors":"Kimberly M. Trevino,&nbsp;Bennett Addison,&nbsp;Angelique Y. Louie,&nbsp;Joel Garcia","doi":"10.1002/mrc.5369","DOIUrl":"10.1002/mrc.5369","url":null,"abstract":"<p>Spiropyrans belong to a class of photochromic materials that are known to undergo reversible structural changes from ring-closed spiropyran to ring-open merocyanine isomer in response to different external stimuli, such as redox changes. Sensing redox active molecules such as the potent antioxidant glutathione (GSH) is of interest because of the observation that changes in GSH levels are indicative of oxidative stress and correlated with a number of pathological conditions.<span>^1-3</span> Several GSH-responsive spiropyrans have been reported<span>^4-10</span>; however, these spiropyrans exhibited modest sensitivity and selectivity towards the antioxidant. In addition, the specificity of recognition of these photoswitches to GSH remains imperfect. Understanding the structural details of the spiropyran isomers using nuclear magnetic resonance (NMR) spectroscopy may provide insights to how these photoswitches sense GSH. While ¹H NMR spectra of different spiropyrans are readily available in the literature,<span>^11-22</span> the availability of ¹H NMR data of merocyanine species is rising, but still limited.<span>^{9, 23-33}</span> Thiele et al.<span>³⁴</span> provided nearly complete ¹³C chemical shift assignment of the merocyanine species from a light-irradiated spiropyran featuring a nitro substituent in the chromene group and a carboxylic acid attached to the indolic nitrogen (Figure 1a). However, some ¹H and ¹³C assignments, specifically the olefinic protons and carbons (shown in red asterisks in Figure 1a) at the bridging part of the molecule, were inconclusive. NMR characterization of these protons and carbons are important for determining spatial isomers (e.g., <i>cis</i> or <i>trans</i>), an important piece of structural information for understanding the mechanism governing GSH sensing using spiropyrans. Therefore, we report a complete NMR (¹H and ¹³C NMR) characterization of three GSH-stabilized merocyanines: (E)-2-(2-[5-methoxy-1,3,3-trimethyl-3H-indol-1-ium-2-yl]vinyl)phenolate (<b>MC-1</b>), (E)-4-methoxy-2-(2-[1,3,3-trimethyl-3H-indol-1-ium-2-yl]vinyl)phenolate (<b>MC-2</b>), and (E)-4-methoxy-2-(2-[5-methoxy-1,3,3-trimethyl-3H-indol-1-ium-2-yl]vinyl)phenolate (<b>MC-3</b>) from a series of three spiropyrans: 5′-methoxy-1′,3′,3′-trimethylspiro[chromene-2,2′-indoline] (SP-1), 6-methoxy-1′,3′,3′-trimethylspiro[chromene-2,2′-indoline] (SP-2), and 5′,6-dimethoxy-1′,3′,3′-trimethylspiro[chromene-2,2′-indoline] (SP-3) (Figure 1b). These three structures differ in the number of methoxy groups they contain: <b>MC-1</b> bearing a methoxy on the para position of the indoline unit, <b>MC-2</b> bearing a methoxy on the para position of the phenolic oxygen, and <b>MC-3</b> bearing a methoxy on both sides. Comprehensive NMR characterization of GSH-stabilized merocyanines could aid in the identification of stereochemistry ","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5369","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9749424","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Structural elucidation of lactone derivatives from Dendrobium pendulum","authors":"Mao-Sheng Zhang,&nbsp;Yu Jiang,&nbsp;Lei Cheng,&nbsp;Jian-Wen Yang,&nbsp;Min-Jian Dong,&nbsp;Cheng-Xin Sun,&nbsp;Shi-Ji Xiao","doi":"10.1002/mrc.5370","DOIUrl":"10.1002/mrc.5370","url":null,"abstract":"<p>Six lactone derivatives, including four <i>α</i>-pyrones derivatives (<b>1</b>–<b>4</b>), two <i>α</i>-furanone derivatives (<b>5</b> and <b>6</b>), were isolated from the <i>Dendrobium pendulum</i>. Structural elucidation of these undescribed lactone derivatives were accomplished on the basis of detailed nuclear magnetic resonance analysis, and the absolute configurations of compounds <b>1</b>–<b>4</b> were confirmed by electronic circular dichroism (ECD) techniques. The cytotoxic effects of isolated compounds on human breast cancer cell MDA-MB-231 were evaluated by the MTT assay.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-05-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9740791","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Present and future of pure shift NMR in metabolomics","authors":"Xi Chen,&nbsp;Gildas Bertho,&nbsp;Cédric Caradeuc,&nbsp;Nicolas Giraud,&nbsp;Covadonga Lucas-Torres","doi":"10.1002/mrc.5356","DOIUrl":"10.1002/mrc.5356","url":null,"abstract":"<p>NMR is one of the most powerful techniques for the analysis of biological samples in the field of metabolomics. However, the high complexity of fluids, tissues, or other biological materials taken from living organisms is still a challenge for state-of-the-art pulse sequences, thereby limiting the detection, the identification, and the quantification of metabolites. In this context, the resolution enhancement provided by <i>broadband homonuclear decoupling</i> methods, which allows for simplifying ¹H multiplet patterns into singlets, has placed this so-called <i>pure shift</i> technique as a promising approach to perform metabolic profiling with unparalleled level of detail. In recent years, the many advances achieved in the design of <i>pure shift</i> experiments has paved the way to the analysis of a wide range of biological samples with ultra-high resolution. This review leads the reader from the early days of the main <i>pure shift</i> methods that have been successfully developed over the last decades to address complex samples, to the most recent and promising applications of <i>pure shift</i> NMR to the field of NMR-based metabolomics.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-05-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://analyticalsciencejournals.onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5356","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9468797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Echo pulses for background suppression by optimal control","authors":"Hector Javier Cortes Sanchez,&nbsp;Jörn Schmedt auf der Günne","doi":"10.1002/mrc.5354","DOIUrl":"10.1002/mrc.5354","url":null,"abstract":"<p>Materials used to construct magic-angle-spinning NMR probes can contain NMR active nuclei that produce a significant amount of background signal. Because these materials are located outside the sample coil, the use of spatially selective pulses to remove the background is a popular approach for background suppression. However, previously suggested spatially selective pulses suffer from limited excitation bandwidths, which may make them unsuitable for the acquisition of nuclei with a large chemical shift range. Here, a pulse (OC-BACK) is presented, which has been developed by optimal control, which has a flat profile of ~120 kHz with respect to off-resonance effects and extended pass and suppression bands with respect to the nominal nutation frequency. The presented solution is large enough to be effective for background suppression schemes in ¹⁹F magic-angle-spinning NMR at medium and low magnetic fields.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5354","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9587876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A robust t1 noise suppression method in NMR spectroscopy","authors":"Siyuan Wei,&nbsp;Yiming Ding,&nbsp;Kan Song,&nbsp;Zao Liu","doi":"10.1002/mrc.5355","DOIUrl":"https://doi.org/10.1002/mrc.5355","url":null,"abstract":"<p>Artefacts in high-resolution multidimensional nuclear magnetic resonance (NMR) spectra, known as t₁ noise, can significantly downgrade the spectral quality and remain a significant noise source, limiting the sensitivity of most two-dimensional NMR experiments. In addition to highly sensitive hardware and experimental designs, data post-processing is a relatively simple and cost-effective method for suppressing t₁ noise. In this study, histograms and quantiles were used to obtain a robust estimation of noise level. We constructed a weighted matrix to suppress the t₁ noise. The weighted matrix was calculated from the logistic functions, which were adaptively computed from the spectrum. The proposed method is robust and effective in both simulations and actual experiments. Further, it can maintain the quantitative relationship of the spectrogram and is suitable for various complex peak types.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-05-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50128592","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"EPR characterization of Cu/Al-Zr-Ce ethanol dehydrogenation catalysts: Active site development and coking control","authors":"Yuri A. Fionov,&nbsp;Sofia G. Chuklina,&nbsp;Ksenia S. Khlusova,&nbsp;Alexander V. Fionov,&nbsp;Anna I. Zhukova","doi":"10.1002/mrc.5353","DOIUrl":"10.1002/mrc.5353","url":null,"abstract":"<p>Electron paramagnetic resonance (EPR) spectroscopy was applied to study structure–performance relationships for copper-containing catalysts based on Al-Zr-Ce mixed oxides with various oxide support synthesis temperature. <i>In situ</i> EPR showed that the state of Cu²⁺ sites depends on the phase composition of the support, temperature, as well as the presence of the reaction medium during catalysis.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-04-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9945152","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Automated optimization of spatial resolution for single-sided NMR","authors":"Lyndi Kiple,&nbsp;John Ballenger,&nbsp;Kristina Keating,&nbsp;Anagi M. Balachandra,&nbsp;Tyler Meldrum","doi":"10.1002/mrc.5352","DOIUrl":"10.1002/mrc.5352","url":null,"abstract":"<p>Single-sided NMR instruments utilize inhomogeneous magnetic fields with strong gradients to nondestructively probe physical properties of materials. The sensitive region of this type of magnet is often a thin slice above the magnet's surface; measuring planar samples with high spatial resolution requires coplanarity between the sensitive region of the magnet and the sample region of interest. We developed an algorithmic approach to position flat samples coplanar with the magnet's sensitive region. The efficient and objective positioning process utilizes an adjustable stage that offers control over three degrees of freedom, and the optimal position for each sample is found with a quadtree algorithm. We show this algorithm is effective for positioning samples with various relaxation behaviors. We report resolution values that describe position optimization, acquisition constraints, and final spatial resolution for each sample. Measurements after optimized positioning had appropriate spatial resolution to distinguish physical regions of layered samples with different physical properties, namely, relaxation behavior. Our algorithmic positioning process can be implemented for planar samples in research and industrial settings to enhance spatial resolution of single-sided NMR measurements.</p>","PeriodicalId":18142,"journal":{"name":"Magnetic Resonance in Chemistry","volume":null,"pages":null},"PeriodicalIF":2.0,"publicationDate":"2023-04-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/mrc.5352","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"9590586","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}