Parahydrogen‐Induced Carbon‐13 Radiofrequency Amplification by Stimulated Emission of Radiation

Abstract

AbstractThe feasibility of Carbon‐13 Radiofrequency (RF) Amplification by Stimulated Emission of Radiation (C‐13 RASER) is demonstrated on a bolus of liquid hyperpolarized ethyl [1‐13C]acetate. Hyperpolarized ethyl [1‐13C]acetate was prepared via pairwise addition of parahydrogen to vinyl [1‐13C]acetate and polarization transfer from nascent parahydrogen‐derived protons to the carbon‐13 nucleus via magnetic field cycling yielding C‐13 nuclear spin polarization of approximately 6 %. RASER signals were detected from samples with concentration ranging from 0.12 to 1 M concentration using a non‐cryogenic 1.4T NMR spectrometer equipped with a radio‐frequency detection coil with a quality factor (Q) of 32 without any modifications. C‐13 RASER signals were observed for several minutes on a single bolus of hyperpolarized substrate to achieve 21 mHz NMR linewidths. The feasibility of creating long‐lasting C‐13 RASER on biomolecular carriers opens a wide range of new opportunities for the rapidly expanding field of C‐13 magnetic resonance hyperpolarization.