Blümich Bernhard, Singh Kawarpal
Institut für Technische und Makromolekulare Chemie, RWTH Aachen University, Aachen, Germany.
Angew Chem Int Ed Engl. 2018 Jun 11;57(24):6996-7010. doi: 10.1002/anie.201707084. Epub 2017 Dec 12.
NMR spectroscopy is an indispensable method of analysis in chemistry, which until recently suffered from high demands for space, high costs for acquisition and maintenance, and operational complexity. This has changed with the introduction of compact NMR spectrometers suitable for small-molecule analysis on the chemical workbench. These spectrometers contain permanent magnets giving rise to proton NMR frequencies between 40 and 80 MHz. The enabling technology is to make small permanent magnets with homogeneous fields. Tabletop instruments with inhomogeneous fields have been in use for over 40 years for characterizing food and hydrogen-containing materials by relaxation and diffusion measurements. Related NMR instruments measure these parameters in the stray field outside the magnet. They are used to inspect the borehole walls of oil wells and to test objects nondestructively. The state-of-the-art of NMR spectroscopy, imaging and relaxometry with compact instruments is reviewed.
核磁共振光谱法是化学分析中不可或缺的方法,直到最近,它还面临着对空间要求高、购置和维护成本高以及操作复杂等问题。随着适用于化学工作台上小分子分析的紧凑型核磁共振光谱仪的推出,这种情况发生了变化。这些光谱仪包含永久磁铁,可产生40至80 MHz之间的质子核磁共振频率。关键技术是制造具有均匀磁场的小型永久磁铁。具有不均匀磁场的台式仪器已经使用了40多年,用于通过弛豫和扩散测量来表征食品和含氢材料。相关的核磁共振仪器在磁铁外部的杂散场中测量这些参数。它们用于检查油井的井壁并对物体进行无损检测。本文综述了紧凑型仪器在核磁共振光谱法、成像和弛豫测量方面的最新进展。