Dai, Danhua, Vasyl Denysenkov, Elena G. Bagryanskaya, Victor M. Tormyshev, Thomas F. Prisner, and Andrei A. Kuzhelev. “13C Hyperpolarization of Viscous Liquids by Transfer of Solid-Effect 1H Dynamic Nuclear Polarization at High Magnetic Field.” The Journal of Physical Chemistry Letters, August 1, 2023.
https://doi.org/10.1021/acs.jpclett.3c01732.
Dynamic nuclear polarization (DNP) is routinely used as a method for increasing the sensitivity to nuclear magnetic resonance (NMR). Recently, high-field solid-effect DNP in viscous liquids on 1H nuclei was demonstrated using narrow-line polarizing agents. Here we expand the applicability of DNP in viscous media to 13C nuclei. To hyperpolarize 13C nuclei, we combined solid-effect 1H DNP with a subsequent transfer of the 1H polarization to 13C via insensitive nuclei enhanced by polarization transfer (INEPT). We demonstrate this approach using a triarylmethyl radical as a polarizing agent and glycerol-13C3 as an analyte. We achieved 13C enhancement factors of up to 45 at a magnetic field of 9.4 T and room temperature.