Parahydrogen Induced Polarization

Despite wide variety of applications, nuclear magnetic resonance (NMR) suffers from poor sensitivity limited by inherently low values of nuclear polarization. Even in high magnetic fields of modern, high-resolution spectrometers, thermal polarization of nuclei barely reaches level of tens of ppms. A number of hyperpolarization techniques have been developed over the years to enhance NMR signal, by obtaining polarization in nonequilibrium conditions. One of the most promising among them is the hyperpolarization method which uses a hydrogen molecule prepared in a singlet state of nuclear spin. Although hydrogen in this para- state is NMR silent, its polarization can be transferred to the desired molecule and produce greatly enhanced NMR spectra. In my talk I would present the mechanisms and recent developments in parahydrogen-induced polarization based on my visit to the Centre for Hyperpolarisation in Magnetic Resonance (York, UK). Prospects of employing this hyperpolarization technique in zero- and ultra-low-field NMR experiments will also be discussed.