2021 journal article

Background‐Free Proton NMR Spectroscopy with Radiofrequency Amplification by Stimulated Emission Radiation

Angewandte Chemie International Edition, 10.

co-author countries: Germany 🇩🇪 Russian Federation 🇷🇺 United States of America 🇺🇸
author keywords: hyperpolarization; NMR spectroscopy; parahydrogen; RASER
MeSH headings : Body Fluids / chemistry; Contrast Media / analysis; Humans; Magnetic Fields; Proton Magnetic Resonance Spectroscopy
Source: ORCID
Added: October 2, 2021

We report on the utility of Radiofrequency Amplification by Stimulated Emission Radiation (RASER) for background-free proton detection of hyperpolarized biomolecules. We performed hyperpolarization of ≈0.3 M ethyl acetate via pairwise parahydrogen addition to vinyl acetate. A proton NMR signal with signal-to-noise ratio exceeding 100 000 was detected without radio-frequency excitation at the clinically relevant magnetic field of 1.4 T using a standard (non-cryogenic) inductive detector with quality factor of Q=68. No proton background signal was observed from protonated solvent (methanol) or other added co-solvents such as ethanol, water or bovine serum. Moreover, we demonstrate RASER detection without radio-frequency excitation of a bolus of hyperpolarized contrast agent in biological fluid. Completely background-free proton detection of hyperpolarized contrast agents in biological media paves the way to new applications in the areas of high-resolution NMR spectroscopy and in vivo spectroscopy and imaging.