Department of Communication Engineering, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, Xiamen University, Xiamen, China.
NMR Biomed. 2012 Sep;25(9):1088-94. doi: 10.1002/nbm.2773. Epub 2012 Jan 31.
A new pulse sequence based on intermolecular double-quantum coherences was proposed to obtain one-dimensional high-resolution liquid NMR spectra in inhomogeneous magnetic fields via Hadamard encoding. In contrast with the conventional intermolecular multiple-quantum coherences method with a two-dimensional acquisition to obtain one one-dimensional high-resolution spectrum, the new method can provide relatively high-resolution spectra directly through one-dimensional acquisition, and can greatly improve the signal-to-noise ratio of the spectrum within a relatively short acquisition time. Theoretical derivation was performed and analytical expressions of the resulting signals are given. Solution samples in purposely de-shimmed magnetic fields and pig brain tissue samples were tested. The experimental results demonstrate that this sequence can retain useful structural information, even when the field inhomogeneity is sufficiently severe to erase almost all spectral information with conventional one-dimensional single-quantum coherence techniques, and good solvent suppression can be achieved. This method may provide a promising technique for applications in in vivo and in vitro NMR.
提出了一种基于分子间双量子相干的新脉冲序列，通过 Hadamard 编码在不均匀磁场中获得一维高分辨率液体 NMR 谱。与传统的二维采集获得一维高分辨率谱的分子间多次量子相干方法相比，新方法可以通过一维采集直接提供相对高分辨率的谱，并且可以在相对较短的采集时间内大大提高谱的信噪比。进行了理论推导，并给出了所得信号的解析表达式。对有意去磁的磁场中的溶液样品和猪脑组织样品进行了测试。实验结果表明，即使磁场不均匀性严重到足以用传统的一维单量子相干技术几乎消除所有谱信息，该序列也可以保留有用的结构信息，并且可以实现良好的溶剂抑制。该方法可能为体内和体外 NMR 的应用提供一种很有前途的技术。
