Periodic Artifact Suppression for Pure Shift NMR Spectroscopy

Pure shift techniques, as one of the rapidly developing frontiers in nuclear magnetic resonance (NMR) fields, can significantly enhance the resolution of NMR spectrum with a removal of splittings induced by scalar couplings. However, periodic artifacts due to residual scalar couplings during acquisition arise on all direct pure shift spectra, causing severe problems in analysis of complicated samples. Herein, we construct a signal model for the pure shift data and discuss the mechanism of periodic artifacts. Then, based on constraints on the low-rank property of pure shift NMR data, a subsequent artifact-suppression method is proposed to reconstruct a clean pure shift spectrum. With the proposed method, clean ^{\mathbf {1}}\text{H} pure shift spectrum can be obtained from only one experiment, greatly accelerating the experiment time while remaining the accuracy of the quantitative measurement. Experiments on a synthesis NMR signal, a complex sample of quinine with pseudo 2-D acquisition, and a medicine sample of azithromycin with 1-D acquisition are carried out to evaluate the feasibility and universality of the proposed method for different experimental techniques. Both the theoretical analysis and experimental results demonstrate the effectiveness of the proposed method for periodic artifacts suppression on complex samples and its potential for practical applications.