From The DNP-NMR Blog:
Implementation and characterization of flow injection in dissolution dynamic nuclear polarization NMR spectroscopy
Chen, H.Y. and C. Hilty, Implementation and characterization of flow injection in dissolution dynamic nuclear polarization NMR spectroscopy. ChemPhysChem, 2015. 16(12): p. 2646-52.
http://www.ncbi.nlm.nih.gov/pubmed/26139513
The use of dissolution dynamic nuclear polarization (D-DNP) offers substantially increased signals in liquid-state NMR spectroscopy. A challenge in realizing this potential lies in the transfer of the hyperpolarized sample to the NMR detector without loss of hyperpolarization. Here, the use of a flow injection method using high-pressure liquid leads to improved performance compared to the more common gas-driven injection, by suppressing residual fluid motions during the NMR experiment while still achieving a short injection time. Apparent diffusion coefficients are determined from pulsed field gradient echo measurements, and are shown to fall below 1.5 times the value of a static sample within 0.8 s. Due to the single-scan nature of D-DNP, pulsed field gradients are often the only choice for coherence selection or encoding, but their application requires stationary fluid. Sample delivery driven by a high-pressure liquid will improve the applicability of these types of D-DNP advanced experiments.
Go to
The DNP-NMR Blog for more info.