Three-field NMR to preserve hyperpolarized proton magnetization as long-lived states in moderate magnetic fields

This communication describes a three-field experiment where inequivalent scalar coupled spin pairs are hyperpolarized at 3.35 T and 1.2 K by dynamic nuclear polarization (DNP), rapidly transferred to high field (7 T) to prepare a suitable initial condition that is converted adiabatically into a long-lived state (LLS) by shuttling to a ‘low’ magnetic field (2 mT–7 T). Even without applying any rf irradiation to sustain the LLS, it has a lifetime TLLS ≫ T1 in low fields. Finally, the sample is shuttled back to high field for observation under high-resolution conditions.