Hyperpolarized (131)Xe NMR spectroscopy.
Hyperpolarized (131)Xe NMR spectroscopy.
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DOI：
10.1016/j.jmr.2010.10.004
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发表时间：
2011-01
期刊：
影响因子：
--
通讯作者：
Meersmann T
中科院分区：
文献类型：
--
作者：
Stupic KF;Cleveland ZI;Pavlovskaya GE;Meersmann T
在自旋交换光泵浦(SEOP)过程中分离出超极化(HP)131Xe，获得了高达2.2%的自旋极化(即在9.4℃时信号增强了5000倍)。Seop在停流模式下应用了几分钟，这种自旋i=3/2的稀有气体同位素的快速、四极驱动的T1驰豫需要随后快速去除Rb并迅速转移到高磁场区域进行核磁共振检测。由于气相中具有依赖于氙气密度的~(131)Xe四极弛豫，所以SEOP极化建立对氙分压的依赖程度甚至比在~(129)Xe SEOP中观察到的更显著。131Xe是唯一具有正旋磁比的稳定惰性气体同位素，因此显示出与所有其他惰性气体不同的hp信号和热信号之间的相对相位。气相131Xe核磁共振谱显示了表面和磁场相关的四极分裂，发现有额外的气体压力和气体成分依赖。水蒸气的存在可能会影响氙气与表面的相互作用，从而减少了分裂。Hp~(131)Xe谱显示差线展宽，表明存在较强的吸附中心。在~(131)Xe核磁共振谱研究的基础上，给出了自旋核高温热自旋极化P的一般方程。
Hyperpolarized (hp) 131Xe with up to 2.2% spin polarization (i.e., 5000-fold signal enhancement at 9.4 T) was obtained after separation from the rubidium vapor of the spin-exchange optical pumping (SEOP) process. The SEOP was applied for several minutes in a stopped-flow mode, and the fast, quadrupolar-driven T1 relaxation of this spin I = 3/2 noble gas isotope required a rapid subsequent rubidium removal and swift transfer into the high magnetic field region for NMR detection. Because of the xenon density dependent 131Xe quadrupolar relaxation in the gas phase, the SEOP polarization build-up exhibits an even more pronounced dependence on xenon partial pressure than that observed in 129Xe SEOP. 131Xe is the only stable noble gas isotope with a positive gyromagnetic ratio and shows therefore a different relative phase between hp signal and thermal signal compared to all other noble gases. The gas phase 131Xe NMR spectrum displays a surface and magnetic field dependent quadrupolar splitting that was found to have additional gas pressure and gas composition dependence. The splitting was reduced by the presence of water vapor that presumably influences xenon-surface interactions. The hp 131Xe spectrum shows differential line broadening, suggesting the presence of strong adsorption sites. Beyond hp 131Xe NMR spectroscopy studies, a general equation for the high temperature, thermal spin polarization, P, for spin nuclei is presented.
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影响因子：
--
作者：
ADRIAN, FJ
通讯作者：
ADRIAN, FJ
影响因子：
2.5
作者：
Cleveland, Zackary I.;Pavlovskaya, Galina E.;Meersmann, Thomas
通讯作者：
Meersmann, Thomas
影响因子：
64.8
作者：
ALBERT, MS;CATES, GD;WISHNIA, A
通讯作者：
WISHNIA, A
影响因子：
2.2
作者：
Cleveland, Zackary I.;Pavlovskaya, Galina E.;Meersmann, Thomas
通讯作者：
Meersmann, Thomas
影响因子：
4.4
作者：
Cleveland, ZI;Pavlovskaya, GE;Meersmann, T
通讯作者：
Meersmann, T