Single-scan ultra-selective probing on targeted components from overlapped NMR spectra

Benefitting from the non-invasive and quantitative detection property, liquid NMR spectroscopy shows broad applications in the identification, separation, and structural determination of chemical substances in mixtures. However, its applications, especially to probing complex mixtures that contain abundant components and complicated molecular structures, somewhat encounter the challenge of spectral congestion. In this study, we demonstrate the ultra-selective extraction of targeted components from overlapped NMR spectra for mixture analyses by investigating the applications of the recent 1D selective GEMSTONE-TOCSY approach. This strategy first adopts an ultra-selective chemical shift filter to choose the targeted spins related to the components of interest, even though situated at overlapped spectral regions with decent suppression on unwanted surrounding signals. Sequentially, it utilizes the 1D selective TOCSY scheme to accurately extract total coupling networks associated with targeted spins, and then spectroscopically separate individual components, thus resolving overlapped NMR spectra. Apart from the measurements on electrolyte and sugar mixtures, experimental results demonstrate that it also allows one to analyze heterogeneous biological tissues containing plentiful metabolites and intrinsic field inhomogeneity via specific probe access to targeted components. Therefore, this study demonstrates a useful tool for component analyses and molecular structure measurements on complex chemical and biological mixtures, and it shows promising prospects for wide applications in the fields of chemistry, biology, energy, etc.