Feasibility of Ultrafast Intermolecular Single-Quantum Coherence Spectroscopy in Analysis of Viscous-Liquid Foods

A newly developed nuclear magnetic resonance (NMR) technique, ultrafast intermolecular single-quantum coherence (UF iSQC) spectroscopy, demonstrated its potentials to obtain spectra of viscous-liquid samples in deuterium-free environment. UF iSQC not only inherits the advantage of ultrafast acquisition efficiency of spatial encoding but also keeps the intrinsic merit of immunity of iSQC in inhomogeneous magnetic field. In the present study, UF iSQC spectroscopy is used for the direct analysis of three typical viscous-liquid foods, namely, honey, yogurt, and tomato sauce, and its feasibility is verified by ultrafast acquisition of NMR spectra of these viscous-liquid foods. UF iSQC spectroscopy presents an advantageous alternative to directly detect most components of these samples in favorable spectral information within 1 min, thus saving the trouble of complicated sample pretreatments and tedious shimming processes. Due to the immunity to field inhomogeneity, the UF iSQC technique can be a proper supplement to dilution, extraction NMR, and magic angle spinning. In addition, in comparison with the conventional iSQC method, the acquisition time of the proposed method is greatly reduced due to the introduction of the spatial encoding technique. The lower sensitivity and resolution of UF iSOC spectra than those of dilutions acquired by the conventional NMR method could be improved by some newly developed strategies. Results obtained here demonstrate the potential application of the UF iSQC spectroscopy in the quality control of food.