不均匀不稳定磁场下高分辨液体核磁共振新技术的研究进展

高分辨核磁共振(Nuclear Magnetic Resonance,NMR)谱的获得通常需要高度稳定且均匀的强静磁场.阻抗磁体或阻抗-超导混合磁体可获得比超导磁体高得多的磁场,但它们的磁场的稳定性与均匀性比较差;另一方面,在活体定域波谱研究中,样品内部组分的磁化率差异,运动或生理活动等作用将不可避免地导致磁场的不均匀不稳定,并且这些不稳定不均匀性无法通过锁场匀场等传统的方法消除.基于分子间零量子相干的方法、空间编码单扫描快速方法、反卷积技术等日渐成为在不均匀不稳定磁场下获取高分辨率的NMR谱的研究热点.

Progress of High-Resolution Liquid NMR Spectroscopy in Inhomogeneous and Unstable Fields

Strong and extremely homogeneous and stable static magnetic fields are usually required for high-resolution NMR. However, large inhomogeneity and drift of the magnetic fields exist in the resistive and hybrid magnets which can provide much higher magnetic fields than the superconducting counterpart. On the other hand, the susceptibility gradients and physiological motions in in vivo studies produce inhomogeneous and unstable magnetic fields. Therefore, the inhomogeneous and instable magnetic fields in the non-ideal condition are unavoidable and can hardly be eliminated by conventional methods such as shimming and locking. Some approaches had been proposed to obtain high-resolution NMR spectra in the inhomogeneous and instable field, such as intermolecular zero quantum coherences (iZQCs), spatially encoding single-scan scheme and deconvolution. In the paper, these four methods were discussed.