Physics Department & Shanghai Key Laboratory of Magnetic Resonance, East China Normal University, Shanghai 200062, China.
J Magn Reson. 2011 Oct;212(2):455-9. doi: 10.1016/j.jmr.2011.07.025. Epub 2011 Aug 10.
Dipolar filters are of considerable importance for eliminating the (1)H NMR signal of the rigid components of heterogeneous compounds while selecting the signal of their mobile parts. On the basis of such filters, structural and dynamical information of these compounds can often be acquired through further manipulations (e.g. spin diffusion) on the spin systems. To overcome the destructive interferences between the magic angle spinning (MAS) speed and the cycle-time of the widely-used Rotor-Asynchronized Dipolar Filter (RADF) sequence, we introduce a new method called Rotor-Synchronized Dipolar Filter (RSDF). This communication shows that this sequence does not present any interference with the spinning speed and is more compatible than RADF with high MAS frequencies (ν(R)>12 kHz). This new pulse sequence will potentially contribute to future researches on heterogeneous materials, such as multiphase polymer and membrane systems.
双极滤波器在消除不均匀化合物中刚性成分的 (1)H NMR 信号，同时选择其移动部分的信号方面具有重要意义。基于这些滤波器，通过对自旋系统进行进一步的操作（例如自旋扩散），通常可以获得这些化合物的结构和动力学信息。为了克服魔角旋转（MAS）速度和广泛使用的转子非同步双极滤波器（RADF）序列的循环时间之间的破坏性干扰，我们引入了一种称为转子同步双极滤波器（RSDF）的新方法。本通讯表明，该序列不会对旋转速度产生任何干扰，并且与 RADF 相比，它与高 MAS 频率（ν(R)>12 kHz）更兼容。这个新的脉冲序列将有可能对多相聚合物和膜系统等不均匀材料的未来研究做出贡献。
