[Development of Benchtop Low‑Field Nuclear Magnetic Resonance Technology and Its Application in Drug Control Field]

At present, the drug substitutes represented by new psychoactive substances are gradually becoming popular, leading to an increasing demand for identifying novel drugs with unknown structures in drug investigation. Nuclear magnetic resonance (NMR) spectroscopy is an important tool for analyzing molecular structures. In the absence of standard substances, quantitative NMR (qNMR) can undertake the quantitative analysis of target substances in complex mixtures and has unique advantages in the research of new drugs and their precursor drugs. Due to the limitations of the site and maintenance costs, as well as relatively complex operation, high-field superconducting NMR is less commonly applied in drug research. The desktop low‑field NMR developed in recent years provides a new alternative solution. Due to the use of permanent magnets, its size is reduced, and the operation and maintenance costs are lowered. It has been widely used in various research fields. This article reviews the development of low-field NMR technology, summarizes the application of desktop low-field NMR in screening and identification of suspicious substances, rapid content determination, analysis of drug manufacturing processes and synthetic routes, and correlation traceability. It also looks forward to the prospects and development directions of this technology in drug research, aiming to provide a reference for researchers who work in analytical chemistry and drug research.