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Scientific publications

Throughout my scientific career, I have focused extensively on the development of modern liquid-state NMR methods for chemical and biological applications. The outcomes of the research have been published in peer‐reviewed international journals research articles in high-impact peer-reviewed journals (download full list). Take a look here!

  2024

Solvent suppression in pure shift NMR

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Anal. Chem.,  2024, 96, 3879–3885
Emma L. Gates, Jonathan P. Bradley, Daniel B. G. Berry, Mathias Nilsson, Gareth A. Morris, Ralph W. Adams, and Laura Castañar*

Here, we show that by combining WATERGATE solvent suppression with pure shift NMR, ultrahigh-resolution 1H NMR spectra can be acquired while suppressing intense solvent signals and retaining exchangeable 1H signals. The new method is demonstrated in the analysis of two aqueous samples of pharmaceutical relevance.

In situ setup for screening of drug permeation by NMR spectroscopy

Anal. Methods, 2024, 16, 1468-1472
Malte Mildner, Simon Hanio, Sebastian Endres, Lena Scheller, Bettina Engel, Laura Castañar, Lorenz Meinel, and Ann-Christin Pöppler*

Here we explore the use of a custom-built NMR tube and spatially encoded NMR experiments for membrane permeation experiments. Setup-specific challenges and workarounds are discussed.

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  2023

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Lighting up spin systems: enhancing characteristic 1H signal patterns of fluorinated molecules

Chem. Commun., 2023, 59, 11692-11695
Marshall J. Smith, Jack E. Bramham,  Mathias Nilsson, Gareth A. Morris, Laura Castañar*  and  Alexander P. Golovanov*

Combining sample illumination and fluorine-edited selective TOCSY acquisition allows significant enhancements of characteristic 1H signal fingerprints of fluorinated molecules.

Recovering sensitivity lost through convection in pure shift NMR

Chem. Commun., 2023, 59, 12633-12636
Elsa Caytan,  Howard M. Foster, Laura Castañar, Ralph W. Adams, Mathias Nilsson and Gareth A. Morris*  

Pure shift NMR experiments using cryoprobes can give very disappointing results. We show that signal losses and phase distortions are a consequence of sample convection, and demonstrate a simple adjustment that restores the lost signal.

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Rapid measurement of heteronuclear coupling constants in complex NMR spectra

J. Am. Chem. Soc. 2023, 145, 19824–19831
Coral Mycroft, Guilherme Dal Poggetto*, Thaís M. Barbosa, Cláudio F. Tormena, Mathias Nilsson, Gareth A. Morris, and Laura Castañar*

The NMR analysis of fluorine-containing molecules poses significant challenges. .Here, the IPAP-FESTA method is reported that drastically simplifies measurements of the signs and magnitudes of proton–fluorine couplings. 

Ultra-selective 1D clean in-phase correlation spectroscopy

Chem. Commun., 2023, 59, 6734-6737
Daniel A. Taylor, Peter Kiraly, Paul Bowyer, Mathias Nilsson, Laura Castañar, Gareth A. Morris and  Ralph W. Adams*

GEMSTONE CLIP-COSY: a new NMR experiment for determination of the direct bonding network of nuclei whose NMR signals overlap.

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Pure shift FESTA: An ultra-high resolution NMR tool for the analysis of complex fluorine-containing spin systems

Magn. Reson. Chem. 2023, 61, 606–614
Coral Mycroft, Marshall Smith, Mathias Nilsson, Gareth A. Morris, and Laura Castañar*

Pure shift FESTA, a new ultra-high resolution 1H NMR method that allows extracting fully decoupled 1H signals of a fluorine-containing spin system from a poorly resolved 1H NMR spectrum. 

Pure shift 2D NMR spectroscopy

Fast 2D Solution-state NMR: Concepts and Applications, Chapter 8. The Royal Society of Chemistry, 2023. 
Ralph W. Adams and Laura Castañar*  

This chapter introduces pure shift NMR spectroscopy and shows how it can be combined with 2D methods to simplify spectra and aid interpretation. Despite not being intrinsically quick to acquire, as pure shift methods provide direct access to spectral information that might otherwise require much more time-consuming methods they warrant a position alongside fast 2D NMR methods.

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Ultra-selective, ultra-clean 1D rotating-frame Overhauser effect spectroscopy

Chem. Commun., 2023, 59, 5854-5857
Emma L. Gates, Marshall J. Smith, Jonathan P. Bradley, Myron Johnson, Göran Widmalm, Mathias Nilsson, Gareth A. Morris, Ralph W. Adams* and Laura Castañar*

A new ultra-selective 1D ROESY method which enables clear, unambiguous assignment of through-space interactions, providing insight into 3D structure and conformation.

Relaxational signal attenuation during soft refocusing pulses

Magn. Reson. Chem. 2023, 61, 606–614
Runchao Li, Laura Castañar, Mathias Nilsson, and Gareth A. Morris*

Here it is shown that relaxation during selective 180° refocusing pulses can be well represented by biexponential decay, with rate constants R2 and a linear combination of R1 and R2, allowing correction for relaxational losses in experiments using selective refocusing pulses.

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  2022

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Simultaneous broadband suppression of homonuclear and heteronuclear couplings in      1H NMR spectroscopy

ChemPhysChem., 2022, 23, e2022004
Coral Mycroft, Mathias Nilsson, Gareth A. Morris, and Laura Castañar*

Ultra-high resolution 1H NMR spectra are obtained by simultaneous broadband suppression of both homonuclear and heteronuclear scalar couplings, giving a fully pure shift 1H NMR spectrum containing chemical shift information only. 

Giving pure shift NMR spectroscopy a REST:  ultrahigh resolution mixture analysis

Anal. Chem., 2022, 94, 12757-12761
Marshall. J. Smith, Laura Castañar, Ralph W. Adams, Gareth A. Morris, and Mathias Nilsson*

Pure shift NMR experiments using cryoprobes can give very disappointing results. We show that signal losses and phase distortions are a consequence of sample convection, and demonstrate a simple adjustment that restores the lost signal.

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Improved quantification by NMR spectroscopy of the fatty acid ester composition of extra virgin olive oils

Anal. Chem. 2022, 94, 12757-12761
Gabriel Rosseto, Peter Kiraly, Laura. Castañar, Gareth A. Morris, and Mathias Nilsson*

Here, we show the utility of DISPEL, an experiment able to suppress 13C satellites and to improve the accuracy of integration of minor signals, for quantitative analysis of olive oil.

  2021

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Broadband measurement of true transverse relaxation rates in systems with coupled protons: application to the study of conformational exchange

ChemChem. Sci., 2021, 12, 11538–11547
Peter Kiraly, Guilherme Dal Poggetto, Laura Castañar, Mathias Nilsson, Andrea Deák, Gareth A. Morris

Ultra-high resolution 1H NMR spectra are obtained by simultaneous broadband suppression of both homonuclear and heteronuclear scalar couplings, giving a fully pure shift 1H NMR spectrum containing chemical shift information only. 

Giving pure shift NMR spectroscopy a REST:  ultrahigh resolution mixture analysis

Anal. Chem., 2022, 94, 12757-12761
Marshall. J. Smith, Laura Castañar, Ralph W. Adams, Gareth A. Morris, and Mathias Nilsson*

Pure shift NMR experiments using cryoprobes can give very disappointing results. We show that signal losses and phase distortions are a consequence of sample convection, and demonstrate a simple adjustment that restores the lost signal.

TOC_4.tif
dispel-oil.gif

Improved quantification by NMR spectroscopy of the fatty acid ester composition of extra virgin olive oils

Anal. Chem. 2022, 94, 12757-12761
Gabriel Rosseto, Peter Kiraly, Laura. Castañar, Gareth A. Morris, and Mathias Nilsson*

Here, we show the utility of DISPEL, an experiment able to suppress 13C satellites and to improve the accuracy of integration of minor signals, for quantitative analysis of olive oil.

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