The ZULF spectra of hyperpolarized samples HP1 and HP2 are shown in Fig. . A thermal-reference spectrum with prepolarization at 2 T averaged over sixteen scans of a sample of 5. Experimental sequence from hyperpolarization in the solid state at 1.2 K and 7.05 T to detection in the liquid state at zero magnetic field. The gray blocks "µw", "CP", and "Inv" represent µw irradiation, polarization transfer from 1 H to 13 C by cross polarization and adiabatic-inversion pulse acting on 13 C spins, respectively. The numbers n and m correspond to the number of 13 C detection blocks between each CP contact and the total number of CP contacts in the hyperpolarization scheme, respectively. Typically n = 6 and m ≥ 6. Note that the 2 T magnet is omitted in the magnetic field profile of the experimental sequence.