HIGH-FREQUENCY (140 GHZ) DYNAMIC NUCLEAR-POLARIZATION - POLARIZATION TRANSFER TO A SOLUTE IN FROZEN AQUEOUS-SOLUTION

Dynamic nuclear polarization (DNP) transfers the large polarization of unpaired electrons to nuclei and thus significantly enhances the signal strength in nuclear magnetic resonance (NMR) spectroscopy. High frequency/field (140 GHz/5 T) DNP has been implemented in solid state NMR experiments using a nitroxide radical as the paramagnetic polarizing agent in a watenglycerol frozen solution. The 1H and 13C NMR signal strengths of both the solvent and an amino acid solute have been enhanced by a factor of 185, which represents a reduction of >102 in sample size requirements or >104 in signal acquisition time. © 1995 American Institute of Physics.