Buchberger Kathrin, Walenta Martin, Zangger Klaus
Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse 28, A-8010, Graz, Austria.
Magn Reson Chem. 2018 Oct;56(10):934-940. doi: 10.1002/mrc.4699. Epub 2018 Jan 7.
The measurement of small homonuclear coupling constants is often prevented by either their small size and/or overlap with other signal splittings. Here, we present a real-time method to extract such couplings without interference from other splittings, with a resolution that is beyond conventional NMR spectra. In this real-time J-upscaled SERF experiment, homonuclear coupling is removed by slice-selective pure shift NMR, whereas scalar coupling to only one selected signal is reintroduced by selective refocusing. The remaining couplings are enhanced by real-time J-upscaling during interruptions of the FID data acquisition. The resulting spectrum is not only simplified by the restriction of the scalar coupling but also its resolution enhanced. This improved resolution results from a reduction of signal broadening due to magnetic field inhomogeneities from 2 different sources: slice-selective excitation and the spin-echo type J-upscaling element.
小的同核耦合常数的测量常常因其数值小和/或与其他信号分裂重叠而受阻。在此，我们提出一种实时方法，可在不受其他分裂干扰的情况下提取此类耦合，其分辨率超越传统核磁共振谱。在这个实时J增强SERF实验中，同核耦合通过切片选择性纯位移核磁共振去除，而仅与一个选定信号的标量耦合通过选择性重聚焦重新引入。在FID数据采集中断期间，通过实时J增强来增强剩余的耦合。所得谱图不仅因标量耦合的限制而简化，其分辨率也得到提高。这种分辨率的提高源于两种不同来源的磁场不均匀性导致的信号展宽的减少：切片选择性激发和自旋回波型J增强元件。
