Kouřil Karel, Kouřilová Hana, Bartram Samuel, Levitt Malcolm H, Meier Benno
School of Chemistry, University of Southampton, Southampton, SO17 1BJ, United Kingdom.
Nat Commun. 2019 Apr 15;10(1):1733. doi: 10.1038/s41467-019-09726-5.
In dissolution-dynamic nuclear polarization, nuclear spins are hyperpolarized at cryogenic temperatures using radicals and microwave irradiation. The hyperpolarized solid is dissolved with hot solvent and the solution is transferred to a secondary magnet where strongly enhanced magnetic resonance signals are observed. Here we present a method for transferring the hyperpolarized solid. A bullet containing the frozen, hyperpolarized sample is ejected using pressurized helium gas, and shot into a receiving structure in the secondary magnet, where the bullet is retained and the polarized solid is dissolved rapidly. The transfer takes approximately 70 ms. A solenoid, wound along the entire transfer path ensures adiabatic transfer and limits radical-induced low-field relaxation. The method is fast and scalable towards small volumes suitable for high-resolution nuclear magnetic resonance spectroscopy while maintaining high concentrations of the target molecule. Polarization levels of approximately 30% have been observed for 1-C-labelled pyruvic acid in solution.
在溶解动态核极化中，利用自由基和微波辐射在低温下使核自旋超极化。将超极化的固体用热溶剂溶解，然后将溶液转移到二级磁体中，在那里可观察到强烈增强的磁共振信号。在此，我们提出一种转移超极化固体的方法。使用加压氦气将装有冷冻超极化样品的子弹射出，射入二级磁体中的接收结构，子弹在那里被保留，极化固体迅速溶解。转移过程大约需要70毫秒。沿着整个转移路径缠绕的螺线管可确保绝热转移，并限制自由基引起的低场弛豫。该方法速度快且可扩展至适合高分辨率核磁共振光谱的小体积，同时保持目标分子的高浓度。在溶液中，已观察到1-C标记的丙酮酸的极化水平约为30%。
