Resolution of (129)Xe chemical shifts at ultralow magnetic field.

In high-field nuclear magnetic resonance (NMR) spectroscopy, the sensitivity of the xenon chemical shift to its environment1 has been exploited to study porosity and surface interactions in materials2, as well as to probe xenon interactions with molecules3 and proteins4 in solution. In recent years, polarization enhancement through optical pumping5 techniques has further advanced the utility of xenon NMR6 and magnetic resonance imaging (MRI) from high7 (several Tesla) to ultralow magnetic fields.8,9 Despite the emergence of research in low-field MRI using laser-polarized xenon, the chemical shift of 129Xe, widely studied and used at high fields, still remains unexploited at mT fields. The possibility