Polarization transfer using hyperpolarized, supercritical xenon

Polarization transfer from hyperpolarized gas to H-1, C-13, etc. holds grea t promise for sensitivity enhancement of solution-state NMR. The route expl ored here uses hyperpolarized, supercritical xenon as solvent for the organ ic solute. A method is described for preparation of supercritical xenon sol utions with little polarization loss. Detection of Overhauser enhancement o f solute proton magnetization by factors of 3 to 7 confirms the intimate co ntact between Xe-129 and H-1. Motivated by more efficient polarization tran sfer expected in solid solutions, we report survival of non-equilibrium sol ute polarization upon warming from solid to supercritical fluid. (C) 2000 P ublished by Elsevier Science B.V.