FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany.
FG Technische Physik II/Polymerphysik, Technische Universität Ilmenau, D-98684 Ilmenau, Germany.
J Magn Reson. 2019 Oct;307:106583. doi: 10.1016/j.jmr.2019.106583. Epub 2019 Aug 23.
Dynamic Nuclear Polarization methods are used for improving the quality of the NMR data, opening new possibilities by increasing both the sensitivity and the selectivity in NMR relaxation experiments. Recently, Fast Field Cycling relaxometry combined with DNP was introduced, demonstrating that molecular dynamics studies in the presence of natural or artificial radicals are indeed feasible under conditions where the signal-to-noise ratio is frequently critical. In this work, the extension of NMR relaxation dispersion beyond H NMR, by hyperpolarization of X-nuclei, is demonstrated. Overhauser effect via nitroxide radicals in simple (low viscous) liquids and saline solutions was observed for H, Li and C nuclei at ambient temperature. Substantial NMR signal enhancement up to several hundred was achieved for the studied samples. An advanced approach for reconstructing of the original relaxation dispersion of pure substances is used to eliminate the effect of the additional radical relaxivity of the X-nuclei.
动态核极化方法用于提高 NMR 数据的质量，通过增加 NMR 弛豫实验的灵敏度和选择性，开辟了新的可能性。最近，结合 DNP 的快速场循环弛豫测量技术已经被引入，证明了在天然或人工自由基存在的情况下，在信号噪声比经常是关键的条件下，分子动力学研究是可行的。在这项工作中，通过 X-核的极化，展示了超越 H NMR 的 NMR 弛豫分散的扩展。室温下，在简单（低粘性）液体和盐溶液中，通过氮氧自由基观察到 H、Li 和 C 核的 Overhauser 效应。研究样品的 NMR 信号增强了数百倍。使用一种先进的方法来重建纯物质的原始弛豫分散，以消除 X-核的额外自由基弛豫率的影响。
