Comparison of various sampling schemes and accumulation profiles in covariance spectroscopy with exponentially decaying 2D signals
Comparison of various sampling schemes and accumulation profiles in covariance spectroscopy with exponentially decaying 2D signals
复制标题
协方差光谱中各种采样方案和累积曲线与指数衰减二维信号的比较
DOI：
10.1039/c3an36375a
复制
发表时间：
2013-01-01
期刊：
影响因子：
4.2
通讯作者：
Deng, Feng
中科院分区：
文献类型：
--
作者：
Li, Yixuan;Hu, Bingwen;Deng, Feng
二维协方差（COV2D）光谱提供了一种替代二维傅里叶变换（FT 2D）的方法来获得同质核相关NMR光谱。在不损失分辨率的情况下，通过将COV2D与以下结合可以实现实验时间的相当大的节省：（i）具有t（1）截止值（CUO）的均匀采样或非均匀采样（NUS），以及（ii）恒定或高斯累积曲线。我们发现，协方差处理，结合CUO采样和高斯累积配置文件提供了更好的增益在实验时间，相对于所需的FT2D NMR。这与用于2D光谱的最大熵（MaxEnt）重建形成对比，最大熵重建与NUS方案一起工作比与CUO方案一起工作更好。我们进一步讨论了定义这种最佳采集的实验条件，并解释了如何根据所需的分辨率轻松“动态”优化这些参数，这与样本密切相关。
Two-dimensional covariance (COV2D) spectroscopy offers an alternative approach to 2D Fourier transformation (FT2D) to obtain homo-nuclear correlation NMR spectra. Considerable saving in experimental time, without loss of resolution, can be achieved by incorporating COV2D with: (i) uniform sampling with a t(1) cut-off (CUO) or non-uniform sampling (NUS), and (ii) constant or Gaussian accumulation profiles. We find that covariance treatment, combined with the CUO sampling and Gaussian accumulation profile provides better gain in experimental time, with respect to that required with FT2D NMR. This is in contrast with the maximum entropy (MaxEnt) reconstruction for 2D spectra, which works better with the NUS scheme rather than with the CUO scheme. We further discuss the experimental conditions that define this optimum acquisition, and explain how these parameters can easily be optimized 'on the fly' according to the desired resolution, which is quite sample-dependent.