TY - JOUR

T1 - Through-Space Multinuclear Magnetic Resonance Signal Enhancement Induced by Parahydrogen and Radiofrequency Amplification by Stimulated Emission of Radiation

AU - Salnikov, Oleg G.

AU - Trofimov, Ivan A.

AU - Pravdivtsev, Andrey N.

AU - Them, Kolja

AU - Hövener, Jan Bernd

AU - Chekmenev, Eduard Y.

AU - Koptyug, Igor V.

N1 - Funding Information: O.G.S. thanks the Council on Grants of the President of the Russian Federation (grant MK-2826.2022.1.3) and the Russian Foundation for Basic Research (grant 19-33-60045) for the support of RASER studies. I.A.T. thanks the Russian Science Foundation (grant 21-73-10105) for the support of PRINOE hyperpolarization experiments. The Novosibirsk team thanks the Russian Ministry of Science and Higher Education for the access to NMR equipment. A.N.P., J.B.H., and K.T. acknowledge funding from the German Federal Ministry of Education and Research (BMBF) within the framework of the e:Med research and funding concept (01ZX1915C), DFG (PR 1868/3-1, HO-4602/2-2, HO-4602/3 GRK2154-2019, EXC2167, FOR5042, SFB1479, and TRR287). MOIN CC was founded by a grant from the European Regional Development Fund (ERDF) and the Zukunftsprogramm Wirtschaft of Schleswig-Holstein (project no. 122-09-053). E.Y.C. thanks the following for funding support: NSF under Grant CHE-1904780, the National Cancer Institute under 1R21CA220137 DOD CDMRP under W81XWH-20-10576, NIBIB under R01EB029829, and NHLBI R21 HL154032. Publisher Copyright: © 2022 American Chemical Society.

PY - 2022/11/1

Y1 - 2022/11/1

N2 - Hyperpolarized (i.e., polarized far beyond the thermal equilibrium) nuclear spins can result in the radiofrequency amplification by stimulated emission of radiation (RASER) effect. Here, we show the utility of RASER to amplify nuclear magnetic resonance (NMR) signals of solute and solvent molecules in the liquid state. Specifically, parahydrogen-induced RASER was used to spontaneously enhance nuclear spin polarization of protons and heteronuclei (here 19F and 31P) in a wide range of molecules. The magnitude of the effect correlates with the T1 relaxation time of the target nuclear spins. A series of control experiments validate the through-space dipolar mechanism of the RASER-assisted polarization transfer between the parahydrogen-polarized compound and to-be-hyperpolarized nuclei of the target molecule. Frequency-selective saturation of the RASER-active resonances was used to control the RASER and the amplitude of spontaneous polarization transfer. Spin dynamics simulations support our experimental RASER studies. The enhanced NMR sensitivity may benefit various NMR applications such as mixture analysis, metabolomics, and structure determination.

AB - Hyperpolarized (i.e., polarized far beyond the thermal equilibrium) nuclear spins can result in the radiofrequency amplification by stimulated emission of radiation (RASER) effect. Here, we show the utility of RASER to amplify nuclear magnetic resonance (NMR) signals of solute and solvent molecules in the liquid state. Specifically, parahydrogen-induced RASER was used to spontaneously enhance nuclear spin polarization of protons and heteronuclei (here 19F and 31P) in a wide range of molecules. The magnitude of the effect correlates with the T1 relaxation time of the target nuclear spins. A series of control experiments validate the through-space dipolar mechanism of the RASER-assisted polarization transfer between the parahydrogen-polarized compound and to-be-hyperpolarized nuclei of the target molecule. Frequency-selective saturation of the RASER-active resonances was used to control the RASER and the amplitude of spontaneous polarization transfer. Spin dynamics simulations support our experimental RASER studies. The enhanced NMR sensitivity may benefit various NMR applications such as mixture analysis, metabolomics, and structure determination.

UR - http://www.scopus.com/inward/record.url?scp=85141743110&partnerID=8YFLogxK

U2 - 10.1021/acs.analchem.2c02929

DO - 10.1021/acs.analchem.2c02929

M3 - Article

C2 - 36264746

AN - SCOPUS:85141743110

VL - 94

SP - 15010

EP - 15017

JO - Analytical Chemistry

JF - Analytical Chemistry

SN - 0003-2700

IS - 43

ER -