Fundamental and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, WA 99354, USA.
J Magn Reson. 2011 Oct;212(2):378-85. doi: 10.1016/j.jmr.2011.07.019. Epub 2011 Jul 31.
A high-pressure magic angle spinning (MAS) NMR capability, consisting of a reusable high-pressure MAS rotor, a high-pressure rotor loading/reaction chamber for in situ sealing and re-opening of the high-pressure MAS rotor, and a MAS probe with a localized RF coil for background signal suppression, is reported. The unusual technical challenges associated with development of a reusable high-pressure MAS rotor are addressed in part by modifying standard ceramics for the rotor sleeve by abrading the internal surface at both ends of the cylinder. In this way, not only is the advantage of ceramic cylinders for withstanding very high-pressure utilized, but also plastic bushings can be glued tightly in place so that other removable plastic sealing mechanisms/components and O-rings can be mounted to create the desired high-pressure seal. Using this strategy, sealed internal pressures exceeding 150 bars have been achieved and sustained under ambient external pressure with minimal loss of pressure for 72 h. As an application example, in situ(13)C MAS NMR studies of mineral carbonation reaction intermediates and final products of forsterite (Mg(2)SiO(4)) reacted with supercritical CO(2) and H(2)O at 150 bar and 50°C are reported, with relevance to geological sequestration of carbon dioxide.
一种高压魔角旋转（MAS）NMR 能力，包括一个可重复使用的高压 MAS 转子、一个用于原位密封和重新打开高压 MAS 转子的高压转子加载/反应室，以及一个带有局部 RF 线圈的 MAS 探头，用于抑制背景信号。通过在圆柱体的两端研磨转子套管的内部表面，部分解决了开发可重复使用的高压 MAS 转子所涉及的不寻常的技术挑战。通过这种方式，不仅利用了陶瓷圆柱体能够承受非常高压力的优势，而且还可以将塑料衬套紧紧地粘在适当的位置，以便可以安装其他可移动的塑料密封机构/组件和 O 形圈，以形成所需的高压密封。使用这种策略，在环境外部压力下，已实现并维持超过 150 巴的密封内部压力，压力损失最小，持续时间为 72 小时。作为应用示例，报告了在 150 巴和 50°C 下用超临界 CO2和 H2O 与镁橄榄石（Mg2SiO4）反应的矿物碳酸化反应中间体和最终产物的原位（13）C MAS NMR 研究，这与二氧化碳的地质封存有关。
