Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
J Chem Phys. 2009 Dec 14;131(22):224516. doi: 10.1063/1.3266422.
Two-dimensional nuclear magnetic resonance (2D NMR) spectroscopy provides the means to extract diverse physical, chemical, and biological information at an atomic level. Conventional sampling schemes, however, may result in relatively long 2D experiments; this has stimulated the search for alternative, rapid acquisition schemes. Among the strategies that have been recently proposed for achieving this counts an "ultrafast" approach, relying on the spatial encoding of the indirect domain evolution to provide arbitrary spectra within a single scan. A common feature of all spatial encoding schemes hitherto described is their uniform encoding of a continuous bandwidth of indirect-domain frequencies, regardless of the chemical sites' spectral distribution within it. These very general conditions, however, are often associated with a number of tradeoffs and compromises in the spectral widths and resolutions that can be achieved for both the direct and indirect domains. This paper proposes a different strategy for single-scan acquisition of 2D spectra, which performs an optimal encoding by employing a priori information regarding the positions of NMR resonances along the indirect domain. We denote this as "spatial/spectral encoding"; the underlying principles of this new approach, together with experimental results based on uni- and multidimensional rf pulse schemes, are presented.
二维核磁共振（2D NMR）光谱学提供了在原子水平上提取各种物理、化学和生物学信息的手段。然而，传统的采样方案可能导致相对较长的 2D 实验；这刺激了对替代快速采集方案的探索。最近提出的实现这一目标的策略之一是“超快”方法，依赖于间接域演化的空间编码，在单个扫描中提供任意谱。迄今为止描述的所有空间编码方案的一个共同特征是它们对间接域频率的连续带宽进行均匀编码，而不管其中化学位点的光谱分布如何。然而，这些非常一般的条件通常与在直接和间接域中可以实现的谱宽和分辨率方面的许多权衡和妥协相关联。本文提出了一种用于单扫描采集 2D 光谱的不同策略，通过利用关于间接域中 NMR 共振位置的先验信息来执行最佳编码。我们将其称为“空间/谱编码”；介绍了这种新方法的基本原理以及基于单维和多维射频脉冲方案的实验结果。
