Frozen water NMR lineshape analysis enables absolute polarization quantification

Frozen water NMR lineshape analysis enables absolute polarization quantification Full article

Journal

Physical Chemistry Chemical Physics
ISSN: 1463-9076

Output data

Year: 2022, Volume: 24, Number: 10, Pages: 5956-5964 Pages count : 10 DOI: 10.1039/d1cp05127j

Authors

Koptyug Igor V. ¹ , Stern Quentin ² , Jannin Sami ² , Elliott Stuart J. ²

Affiliations

1	International Tomography Center, SB RAS, 3A Institutskaya St., Novosibirsk, 630090, Russia
2	Univ. Lyon, CNRS, ENS Lyon, UCBL, Université de Lyon, CRMN UMR 5280, 69100 Villeurbanne, France

Typical magnetic resonance experiments are routinely limited by weak signal responses. In some cases, the low intrinsic sensitivity can be alleviated by the implementation of hyperpolarization technologies. Dissolution-dynamic nuclear polarization offers a means of hyperpolarizing small molecules. Hyperpolarized water is employed in several dynamic nuclear polarization studies, and hence accurate and rapid quantification of the 1H polarization level is of utmost importance. The solid-state nuclear magnetic resonance spectrum of water acquired under dissolution-dynamic nuclear polarization conditions has revealed lineshapes which become asymmetric at high levels of 1H polarization, which is an interesting fundamental problem in itself, but also complicates data interpretation and can prevent correct estimations of polarization levels achieved. In previous studies, attempts to simulate the 1H spectral lineshape of water as a function of the 1H polarization led to significant disagreement with the experimental results. Here we propose and demonstrate that such simulations, and therefore polarization quantification, can be implemented accurately, in particular by taking into account the detector dead time during 1H signal acquisition that can lead to severe spectral distortions. Based on these findings, we employed an echo-based radiofrequency pulse sequence to achieve distortion-free 1H spectra of hyperpolarized water, and adequate simulations of these echo-based spectra were implemented to extract the absolute 1H polarization level from the hyperpolarized water signal only, thus alleviating the need for lengthy and insensitive measurements of thermal equilibrium signals.

Koptyug I.V. , Stern Q. , Jannin S. , Elliott S.J.
Frozen water NMR lineshape analysis enables absolute polarization quantification
Physical Chemistry Chemical Physics. 2022. V.24. N10. P.5956-5964. DOI: 10.1039/d1cp05127j WOS Scopus OpenAlex

Submitted:	Nov 9, 2021
Published online:	Feb 15, 2022
Published print:	Mar 14, 2022

≡ Web of science:	WOS:000759742600001
≡ Scopus:	2-s2.0-85126072718
≡ OpenAlex:	W4212971525