Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan.
Phys Chem Chem Phys. 2012 Jul 21;14(27):9715-21. doi: 10.1039/c2cp41191a. Epub 2012 Jun 8.
Two-dimensional (2D) covariance NMR spectroscopy, which has originally been established to extract homonuclear correlations (HOMCOR), is extended to include heteronuclear correlations (HETCOR). In a (13)C/(15)N 2D chemical shift correlation experiment, (13)C and (15)N signals of a polycrystalline sample of (13)C, (15)N-labeled amino acid are acquired simultaneously using a dual-receiver NMR system. The data sets are rearranged for the covariance data processing, and the (13)C-(15)N heteronuclear correlations are obtained together with the (13)C-(13)C and (15)N-(15)N homonuclear correlations. The present approach retains the favorable feature of the original covariance HOMCOR that the spectral resolution along the indirect dimension is given by that of the detection dimension. As a result, much fewer amounts of data are required to obtain a well-resolved 2D spectrum compared to the case of the conventional 2D Fourier-Transformation (FT) scheme. Hence, one can significantly save the experimental time, or enhance the sensitivity by increasing the number of signal averaging within a given measurement time.
二维（2D）协方差 NMR 光谱学最初是为提取同核相关（HOMCOR）而建立的，现已扩展到包括异核相关（HETCOR）。在（13）C/（15）N 2D 化学位移相关实验中，使用双接收 NMR 系统同时采集（13）C、（15）N 标记氨基酸的多晶样品的（13）C 和（15）N 信号。数据集经过协方差数据处理重新排列，获得（13）C-（15）N 异核相关，以及（13）C-（13）C 和（15）N-（15）N 同核相关。本方法保留了原始协方差 HOMCOR 的有利特征，即间接维度上的谱分辨率由检测维度决定。因此，与传统的二维傅里叶变换（FT）方案相比，获得分辨率良好的 2D 谱所需的数据量要少得多。因此，可以通过在给定测量时间内增加信号平均次数来显著节省实验时间，或提高灵敏度。
