Enhancement of SQUID-Detected NMR Signals with Hyperpolarized Liquid [Formula presented] in a [Formula presented] Magnetic Field

We report an enhancement of proton NMR signals by a factor of [Formula presented] by cross polarization with hyperpolarized liquid [Formula presented] in an ultralow magnetic field of [Formula presented]. The NMR signals from cyclopentane, acetone, and methanol are detected using a commercial high-[Formula presented] SQUID magnetometer with a signal-to-noise ratio of up to 1000 from a single [Formula presented] tipping pulse. This technique allows a wide range of low-field NMR measurements and is promising for the detection of intermolecular scalar spin-spin couplings. Scalar intermolecular couplings can produce a shift of the average NMR frequency in a hyperpolarized sample even in the presence of rapid chemical exchange.