Combining Fast\nPure Shift NMR and GEMSTONE-Based Selective\nTOCSY for Efficient NMR Analysis of Complex Systems

As one of the commonly used intact detection techniques,\nliquid\nNMR spectroscopy offers unparalleled insights into the chemical environments,\nstructures, and dynamics of molecules. However, it generally encounters\nthe challenges of crowded or even overlapped spectra, especially when\nprobing complex sample systems containing numerous components and\ncomplicated molecular structures. Herein, we exploit a general NMR\nprotocol for efficient NMR analysis of complex systems by combining\nfast pure shift NMR and GEMSTONE-based selective TOCSY. First, this\nprotocol enables ultrahigh-selective observation on the coupling networks\nthat are totally correlated with targeted resonances or components,\neven where they are situated in severely overlapped spectral regions.\nSecond, pure shift simplification is introduced to enhance the spectral\nresolution and further resolve the subspectra containing spectral\ncongestion, thus facilitating the dissection of overlapped spectra.\nAdditionally, sparse sampling accompanied by spectral reconstruction\nis adopted to significantly accelerate acquisition and improve spectral\nquality. The advantages of this protocol were demonstrated on different\ncomplex sample systems, including a challenging compound of estradiol,\na mixture of sucrose and d-glucose, and natural grape juice,\nverifying its feasibility and power, and boosting the potential application\nlandscapes in various chemical fields.