Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan.
Division of Chemistry, Graduate School of Science, Kyoto University, 606-8502 Kyoto, Japan.
J Magn Reson. 2018 Dec;297:146-151. doi: 10.1016/j.jmr.2018.10.012. Epub 2018 Oct 23.
We propose a variant of covariance NMR spectroscopy, namely, inner-product NMR spectroscopy, originally suggested in Takeda (2015). The mathematical operation of inner-product NMR is the same as that of covariance NMR, except that subtraction of the average value of the variable is intentionally omitted, so that the correspondence of the spectrum with that of conventional two-dimensional Fourier-transformation is established without having to request the average to become vanishingly small. We demonstrate inner-product NMR for C DARR correlation experiments in a polycrystalline sample of C-labeled l-alanine. In covariance, we show that the mixing-time dependence of the peaks is influenced considerably by the choice of the carrier frequency and thereby the center of the spectrum, whereas the inner-product approach is free from such an undesirable effect, while keeping the merit of the covariance NMR.
我们提出了协方差核磁共振光谱学的一种变体，即内积核磁共振光谱学，最初由武田（2015）提出。内积核磁共振的数学运算与协方差核磁共振相同，只是故意省略了变量平均值的减法，因此在不必要求平均值趋近于零时，就可以建立与传统二维傅里叶变换的光谱对应关系。我们在 C 标记的 l-丙氨酸的多晶样品中展示了用于 C-DARR 相关实验的内积 NMR。在协方差中，我们表明，峰的混合时间依赖性受到载波频率的选择以及光谱中心的影响，而内积方法则没有这种不理想的影响，同时保持了协方差 NMR 的优点。
