Optimization and practical implementation of ultrafast 2D NMR experiments

Júnior, Luiz Henrique Keng Queiroz; Ferreira, Antônio G.; Giraudeau, Patrick

doi:10.1590/s0100-40422013000400016

Cited by 10 publications

(6 citation statements)

References 32 publications

(54 reference statements)

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“…Fortunately, numerous methodological developments have contributed to improve the sensitivity, resolution, spectral width and lineshape of UF 2D NMR . The development of practical tools for the implementation and use of this methodology enabled a number of research groups to apply it in various fields, including but not limited to the real‐time study of chemical or biological dynamic processes, the coupling with hyphenated techniques or the acquisition of 2D spectra in inhomogeneous fields . However, UF 2D NMR was also shown to be a promising analytical tool with a high potential for quantitative analysis.…”

Section: Reducing the Experiments Time To Improve The Precisionmentioning

confidence: 99%

Quantitative 2D liquid‐state NMR

Giraudeau

2014

Magnetic Reson in Chemistry

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Two-dimensional (2D) liquid-state NMR has a very high potential to simultaneously determine the absolute concentration of small molecules in complex mixtures, thanks to its capacity to separate overlapping resonances. However, it suffers from two main drawbacks that probably explain its relatively late development. First, the 2D NMR signal is strongly molecule-dependent and site-dependent; second, the long duration of 2D NMR experiments prevents its general use for high-throughput quantitative applications and affects its quantitative performance. Fortunately, the last 10 years has witnessed an increasing number of contributions where quantitative approaches based on 2D NMR were developed and applied to solve real analytical issues. This review aims at presenting these recent efforts to reach a high trueness and precision in quantitative measurements by 2D NMR. After highlighting the interest of 2D NMR for quantitative analysis, the different strategies to determine the absolute concentrations from 2D NMR spectra are described and illustrated by recent applications. The last part of the manuscript concerns the recent development of fast quantitative 2D NMR approaches, aiming at reducing the experiment duration while preserving - or even increasing - the analytical performance. We hope that this comprehensive review will help readers to apprehend the current landscape of quantitative 2D NMR, as well as the perspectives that may arise from it.

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Section: Reducing the Experiments Time To Improve The Precisionmentioning

confidence: 99%

Quantitative 2D liquid‐state NMR

Giraudeau

2014

Magnetic Reson in Chemistry

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111

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“…correlation between two or more nearby chemical processes). Several works exist in the literature in order to get around the time-consumming acquisition problem, specifically for multidimensional COSY data [for example Ultrafast-COSY (Giraudeau et al 2009;Queiroz et al 2013) or PALSY-COSY (Vega et al 2010)]. Compared to 1 H-NMR experiments for instance, the introduction of an additional dimension should allow a better representation of metabolites, a better predictive power and a better biomarker identification.…”

Section: Introductionmentioning

confidence: 99%

Statistical treatment of 2D NMR COSY spectra in metabolomics: data preparation, clustering-based evaluation of the Metabolomic Informative Content and comparison with 1H-NMR

et al. 2015

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Compared with the widely used 1 H-NMR spectroscopy, two-dimensional NMR experiments provide more sophisticated spectra which should facilitate the identification of relevant spectral zones or biomarkers in metabolomics. This paper focuses on 1 H-1 H COrrelation SpectroscopY (COSY) spectral data. In spite of longer inherent acquisition times, it is commonly accepted by users (biologists, healthcare professionals) that the introduction of an additional dimension probably represents a huge qualitative step for investigations in terms of metabolites identification. Moreover, it seems natural that more information leads to more predictive power. But, until now, very few statistical studies clearly proved this assumption. Therefore a fundamental question is ''Is this supplementary information relevant?''. In order to extend the statistical properties developed for 1D spectroscopy to the challenges raised by 2D spectra, a rigorous study of the performances of COSY spectra is needed as a prerequisite. Having introduced new pre-processing concepts, such as the Global Peak List or an ad hoc 2D ''bucketing'', this paper presents an innovative methodology based on multivariate clustering algorithms to evaluate this question. Numerical clustering quality indexes and graphical results are proposed, based both on the spectral presence or absence of peaks (binary position vectors) and on peak intensities, and through different levels of spectral resolution. The second goal of this paper is to compare clustering performances obtained on COSY and on 1 H-NMR spectra, with the aim of understanding to what extent the COSY spectra carry more Metabolomic Informative Content about the signal than 1D ones. The methodology is applied to two real experimental designs involving different groups of spectra (which define the signal): a 4-mixture cell culture media containing various supervised metabolites and a complex human serum based design. It is shown that COSY spectra appear to be statistically powerful and, in addition, provide better clustering results than corresponding 1 H-NMR when using unlabeled information. Consequently, additional information appears to be relevant for metabolomics applications.

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“…From these initial input parameters, our algorithm automatically calculates the UF specific parameters, and the user just needs to set them on the spectrometer. To use this pre‐acquisition macro, a number of general parameters also need to be defined, such as the length of the coil (available from the manufacturer), the maximum gradient strength (which can be obtained either from the manufacturer's specifications or by using simple calibration protocols), the gyromagnetic ratios of the nuclei or the conventional coherence selection gradients.…”

Section: Methodsmentioning

confidence: 99%

“…The UF specific parameters were set from the user‐defined spectral widths and offsets, according to our routine, as described in Table . To set the gradient amplitudes in percentage, we calculated the maximum gradient amplitude ( G max = 0.816 T/m) available on the spectrometer in accordance with the protocol described in Refs . L values are 0.016 and 0.0165 m for the proton and carbon coils, respectively, for the probe used in this study.…”

Section: Methodsmentioning

confidence: 99%

New practical tools for the implementation and use of ultrafast 2D NMR experiments

Pathan

Charrier

Téa

et al. 2013

Magnetic Reson in Chemistry

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Ultrafast (UF) 2D NMR is a very promising methodology enabling the acquisition of 2D spectra in a single scan. In the last few years, the analytical performance of UF 2D NMR has been highly increased, consequently maximizing its range of applications. However, its implementation and use by non-specialists are far from being straightforward, because of the specific acquisition and processing procedures and parameters characterizing UF NMR. To make this methodology implementable and applicable by non-specialists, we developed a simple routine capable of translating conventional parameters (spectral widths and transmitter frequencies) into specific UF parameters (gradient and chirp pulse parameters). This macro was subsequently implemented in a Web page, which is available for external users. Although the algorithm was designed for two widely used 2D experiments, COSY and HSQC, it can easily be extended to any other pulse sequence. The robustness of this routine was verified successfully on a variety of small molecules. We believe that this tool will eliminate much of the technical difficulties related to UF 2D NMR and will make the technique accessible to a wider audience of organic and analytical chemists.

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Optimization and practical implementation of ultrafast 2D NMR experiments

Cited by 10 publications

References 32 publications

Quantitative 2D liquid‐state NMR

Quantitative 2D liquid‐state NMR

Statistical treatment of 2D NMR COSY spectra in metabolomics: data preparation, clustering-based evaluation of the Metabolomic Informative Content and comparison with 1H-NMR

New practical tools for the implementation and use of ultrafast 2D NMR experiments

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