ARTIFACTS IN GRADIENT ENHANCED HSQC

梯度增强的异质结单量子关联 （GEHSQC）实验被广泛使用，特别是作为构建模块， 多维NMR，例如3D NOESY HSQC实验。 然而，仔细检查GEHSQC光谱揭示了大量的 小艺术品 在高动态范围的情况下，这些伪影 可能会干扰光谱解释，因为 与强信号相关的信号可能会掩盖 兴趣 我们试图解释这些文物的来源， 想办法压制他们 结果证明是由 质子标量耦合在反向转移部分的演化 通过一个中继相干转移机制的脉冲序列。 的 伪像表现为涉及远程质子的交叉峰。 产品 伪影形成和实验结果的操作员分析 证明这些伪影的大小可以超过 主峰。 因此，这些文物代表了一个重要的 失去了敏感性。

The Gradient Enhanced Heteronuclear Single Quantum Correlation (GEHSQC) experiment is widely used, especially as a building block in multi-dimensional NMR, for instance in 3D NOESY HSQC experiments. However, close inspection of GEHSQC spectra reveals a large number of small artifacts. In situations of high dynamic range, these artifacts can interfere with spectral interpretation, since the artifacts associated with intense signals can obscure weak correlations of interest. We have sought to explain the origin of these artifacts and find a method to suppress them. They turn out to be caused by the evolution of proton scalar coupling during the back-transfer portion of the pulse sequence via a relayed coherence transfer mechanism. The artifacts appear as cross-peaks involving remote protons. Product operator analysis of artifact formation and experimental results demonstrate that the magnitude of these artifacts can exceed 10% of the main peak. Therefore, these artifacts represent a significant loss in sensitivity.