Tag Archives: sensitivity enhancement

SeRMN contribution to Symmetry 2017 Conference

2017-10-26NMR Events & Courses, Our Research13C-NMR, chirality, enantiodifferentiation, hyperpolarization, nmr, sensitivity enhancementMiriam

Some of the SeRMN staff presented our last research work about chirality at The first International Conference on Symmetry, Symmetry 2017, that took place from16th to 18th October in Barcelona. Find below a summary of our contribution.

Míriam Pérez-Trujillo presented a lecture entitled: “Chiral Recognition by Dissolution Dynamic Nuclear Polarization NMR Spectroscopy”

Abstract: The recognition of enantiomeric molecules by chemical analytical techniques is still a challenge. A method based on d-DNP (dissolution dynamic nuclear polarization) NMR spectroscopy to study chiral recognition was described for the first time [1]. DNP allows boosting NMR sensitivity by several orders of magnitude, overcoming one of the main limitations of NMR spectroscopy [2]. A method integrating d-DNP and ¹³C NMR-aided enantiodifferentiation using chiral solvating agents (CSA) was developed, in which only the chiral analyte was hyperpolarized and selectively observed by NMR. The described method enhances the sensitivity of the conventional NMR-based procedure [3] and lightens the common problem of signal overlapping between analyte and CSA. As proof on concept, racemic metabolite ¹³C-labeled DL-methionine was enantiodifferentiated by a single-scan ¹³C NMR experiment. This method entails a step forward in the chiral recognition of small molecules by NMR spectroscopy; it opens new possibilities in situations where the sensitivity is limited, for example, when low analyte concentration available or when measurement of an insensitive nucleus required. The advantages and current limitations of the method, as well as future perspectives, are discussed.

Chiral Recognition by Dissolution DNP NMR Spectroscopy of 13C-Labeled DL-Methionine

2017-04-25Methods & Applications, Our Publications, Our Research13C-NMR, chiral recognition, chirality, d-DNP NMR, dissolution DNP, enantiodifferentiation, hyperpolarization, nmr, sensitivity enhancementEva

“Chiral Recognition by Dissolution DNP NMR Spectroscopy of ¹³C-Labeled DL-Methionine” By Eva Monteagudo^,Albert Virgili, Teodor Parella and Míriam Pérez-Trujillo^.. Anal. Chem., 2017, 89 (9), pp 4939–4944 DOI: 10.1021/acs.analchem.7b00156

A method based on d-DNP NMR spectroscopy to study chiral recognition is described for the first time. The enantiodifferentiation of a racemic metabolite in a millimolar aqueous solution using a chiral solvating agent was performed. Hyperpolarized ¹³C-labeled DL-methionine enantiomers were differently observed with a single-scan ¹³C NMR experiment, while the chiral auxiliary at thermal equilibrium remained unobserved. The method developed entails a step forward in the chiral recognition of small molecules by NMR spectroscopy, opening new possibilities in situations where the sensitivity is limited, for example, when a low concentration of analyte is available or when the measurement of an insensitive nucleus, like ¹³C, is required. The advantages and current limitations of the method, as well as future perspectives, are discussed.

PhD Thesis: Development and application of modern pure shift NMR techniques and improved HSQC and HSQMBC experiments

2015-07-27Methods & Applications, News from the SeRMN, Our Researchcoupling-constants, enhanced resolution, full sensitivity, HOBS, homonuclear decoupling, HSQC, HSQMBC, perfect HSQC, PhD Thesis, PIP experiments, pure in-phase signals, pure-shift NMR, residual dipolar couplings, SAPS-HSQC, sensitivity enhancementLaura

Last 16^st July 2015 I defended my PhD Thesis entitled: Development and application of modern pure shift NMR techniques and improved HSQC/HSQMBC experiments.

The present doctoral thesis is framed within the Nuclear Magnetic Resonance (NMR) spectroscopy field, more specifically in the design of modern NMR methodologies. The research work carried out is focused on the design and application of new and modern NMR methodologies (i) to perform efficient broadband ¹H homodecoupling in 1D/2D NMR experiments and (ii) to accurately determine homo- and heteronuclear coupling constants in isotropic and anisotropic conditions through improved HSQC and HSQMBC-type experiments. The thesis is presented as a compendium ten (10) publications that have been published in several peer-reviewed international scientific journals as original research papers. Continue reading PhD Thesis: Development and application of modern pure shift NMR techniques and improved HSQC and HSQMBC experiments →

PhD Thesis by Laura Castañar: Pulse Programs and Data Set Examples

2015-05-31Methods & Applications, News from the SeRMN, NMR Events & Courses, Our Publications, Our Researchaligned-media, coupling-constants, enantiodifferentiation, enhanced resolution, full sensitivity, heteronulear coupling constants, HOBS, HOBS-HSQC, HOBS-HSQC-TOCSY, HOBS-HSQMBC, HOBS-TOCSY, homodecoupling, homonuclear decoupling, HSQC, HSQMBC, J-resolved, multi-slice selection, multiple frequency pulses, NUS, one-bond proton-carbon coupling constants, perfect HSQC, PhD Thesis, PIP experiments, proton-carbon coupling constants, proton-proton coupling constants, pure in-phase signals, Pure shift, quantitative nmr, RDCs, Relaxation times, residual dipolar couplings, resolution enhancement, SAPS-HSQC, sensitivity enhancement, sign of coupling constants, spectral aliasing, T1-relaxation, T2-relaxation, two-bonds proton-proton coupling constantsLaura

Development and application of modern pure shift NMR techniques and improved HSQC/HSQMBC experiments

In the following links one can find Data Set Examples of each Publication presented in the Thesis Work, as well as the corresponding Pulse Program Code for Bruker. All 2D spectra have been previously phased and 2ii, 2ir, and 2ri files removed, otherwise data sets would be too big. Continue reading PhD Thesis by Laura Castañar: Pulse Programs and Data Set Examples →

Review – Pure shift NMR experiments: recent developments, methods and applications

2015-05-02Methods & Applications, NMR Bibliography, Our Publications, Our Researchenantiodifferentiation, enhanced resolution, full sensitivity, heteronulear coupling constants, HOBS, HOBS-HSQC, HOBS-HSQMBC, HOBS-TOCSY, homodecoupling, homonuclear decoupling, Pure shift, Relaxation times, resolution enhancement, review, SAPS-HSQC, sensitivity enhancement, T1-relaxation, T2-relaxationLaura

“Broadband ¹H homodecoupled NMR experiments: recent developments, methods and applications” by Laura Castañar and Teodor Parella. Magnetic Resonance in Chemistry, 2015. DOI: 10.1002/mrc.4238

In recent years, a great interest in the development of new broadband ¹H homonuclear decoupled techniques providing simplified J_HH multiplet patterns has emerged again in the field of small molecule NMR. The resulting highly resolved ¹H NMR spectra display resonances as collapsed singlets, therefore minimizing signal overlap and expediting spectral analysis. This review aims at presenting the most recent advances in pure shift NMR spectroscopy, with a particular emphasis to the Zangger–Sterk experiment. Continue reading Review – Pure shift NMR experiments: recent developments, methods and applications →

Implementing homo- and heterodecoupling in region-selective HSQMBC experiments

2013-12-04Methods & Applications, Our Publications, Our Researchband-selective, HOBS, homonuclear decoupling, HSQMBC, IPAP, proton-carbon coupling constants, pure-shift NMR, resolution enhancement, sensitivity enhancementLaura

“Implementing homo- and heterodecoupling in region-selective HSQMBC experiments” by Laura Castañar, Josep Sauri, Pau Nolis, Albert Virgili and Teodor Parella. Journal of Magnetic Resonance 238 (2014) 63-69.

DOI: 10.1016/j.jmr.2013.10.022

A NMR method to enhance the sensitivity and resolution in band-selective long-range heteronuclear correlation spectra is proposed. The excellent in-phase nature of the selHSQMBC experiment allows that homonuclear and/or heteronuclear decoupling can be achieved in the detected dimension of a 2D multiple-bond correlation map, obtaining simplified cross-peaks without their characteristic fine J multiplet structure. The experimental result is a resolution improvement while the highest sensitivity is also achieved. Specifically, it is shown that the 1H-homodecoupled band-selective (HOBS) HSQMBC experiment represents a new way to measure heteronuclear coupling constants from the simplified in-phase doublets generated along the detected dimension.

Pulse Programs Code for Bruker:

Data set Example:

Cyclosporine

References:

“Full sensitivity and enhanced resolution in homodecoupled band-selective NMR experiments” by L. Castañar, P. Nolis, A. Virgili and T. Parella. Chem. Eur. J. 2013, 19, 17283-17286. DOI: https://dx.doi.org/10.1002/chem.201303235

Full sensitivity and enhanced resolution in homodecoupled band-selective NMR experiments

2013-11-13Methods & Applications, Our Publications, Our Researchband-selective, enhanced resolution, full sensitivity, HOBS, HOBS-HSQC, HOBS-TOCSY, homodecoupling, homonuclear decoupling, HSQC, multiple frequency pulses, proton-carbon coupling constants, pure-shift NMR, sensitivity enhancement, TOCSYLaura

“Full sensitivity and enhanced resolution in homodecoupled band-selective NMR experiments” by Laura Castañar, Pau Nolis, Albert Virgili and Teodor Parella. Chem. Eur. J. 2013, 19, 17283-17286.

DOI: 10.1002/chem.201303235

A NMR pulse scheme that provides full sensitivity in homodecouped band-selective NMR experiments is proposed. Continue reading Full sensitivity and enhanced resolution in homodecoupled band-selective NMR experiments →

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