Polychromatic excitation for 1H SABRE polarization transfer in weakly coupled systems at high field

Polychromatic excitation for 1H SABRE polarization transfer in weakly coupled systems at high field Full article

Journal

Journal of Magnetic Resonance
ISSN: 1090-7807

Output data

Year: 2025, Volume: 381, Article number : 107970, Pages count : DOI: 10.1016/j.jmr.2025.107970

Authors

Markelov Danil A ¹ , Kiryutin Alexey S ¹ , Yurkovskaya Alexandra V ¹

Affiliations

1	International Tomography Center, Siberian Branch of the Russian Academy of Science, Institutskaya 3a, Novosibirsk 630090, Russia

Signal Amplification By Reversible Exchange (SABRE) increases NMR sensitivity using parahydrogen as a source of nuclear spin polarization. In SABRE, the to-be-polarized substrate and dihydrogen in bulk form a transient polarization transfer complex (PTC). This study reports high-field 1H polarization transfer via SABRE induced by selective polychromatic excitation of 1H nuclear spins, avoiding a magnetic field-cycling setup and high-power RF pulses. This enables routine SABRE implementation on standard NMR equipment, including MRI scanners. The proposed polychromatic excitation is efficient for the 1H polarization transfer in the PTCs comprising two weakly coupled hydride 1H nuclei, i.e. with a large chemical shift difference . We show that in a single type of the PTC, coherent high-field 1H polarization transfer is driven by double-RF excitation, i.e. applied at two different frequencies simultaneously. In the general case of several PTCs formed by the substrate molecule, the double-RF excitation allows to selectively induce the 1H polarization transfer in the PTC of interest. To maximize the polarization levels achieved when the substrate forms several types of the PTCs, we propose multi-RF excitation, i.e. applied at more than two 1H frequencies simultaneously, as a generalization of the double-RF approach. The maximum 1H signal enhancements at 9.4 T achieved are as follows: −27 for free nicotinamide (−85 for complex-bound), −21 for free 3-methylpyridine (−105 for complex-bound), −23 for pyridine. Remarkably, for all substrates the 1H signal enhancement exceeds that obtained spontaneously in the high-field: ∼3–9 -fold for the free substrates and ∼10–20-fold for the complex-bound substrates.

Markelov D.A. , Kiryutin A.S. , Yurkovskaya A.V.
Polychromatic excitation for 1H SABRE polarization transfer in weakly coupled systems at high field
Journal of Magnetic Resonance. 2025. V.381. 107970 . DOI: 10.1016/j.jmr.2025.107970 WOS OpenAlex

Submitted:	Jun 27, 2025
Accepted:	Sep 27, 2025
Published online:	Oct 14, 2025
Published print:	Dec 1, 2025

Web of science:	WOS:001600012400001
OpenAlex:	W4415227015

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