2D NMR-Based Metabolomics with HSQC/TOCSY NOAH Supersequences

Sensitivity-improved versions of two-dimensional (2D) C-13-H-1 HSQC (heteronuclear single quantum coherence) and HSQC-TOCSY (HSQC-total correlation spectroscopy) NMR experiments optimized for small biological molecules and their complex mixtures encountered in metabolomics are presented that preserve the magnetization of H-1 spins not directly attached to C-13 spins. This allows (i) the application of rapid acquisition techniques to substantially shorten measurement time and (ii) their incorporation into supersequences (NOAH-NMR by ordered acquisition using H-1 detection) for the compact acquisition of multiple 2D NMR data sets with significant gains in sensitivity, resolution, and/or time. The new pulse sequences, which are demonstrated for both metabolite model mixtures and mouse urine, offer an attractive approach for the efficient measurement of multiple 2D NMR spectra (HSQCsi and/or HSQCsi-TOCSY and TOCSY) of metabolomics samples in a single experiment for the accurate and comprehensive identification and quantitation of metabolites. These new methods bring to bear the advantages of 2D NMR to metabolomics studies with larger cohorts of samples.

Automated summary

This study presents sensitivity-improved versions of two-dimensional NMR experiments optimized for small biological molecules encountered in metabolomics, allowing for rapid acquisition techniques and incorporation into supersequences for compact acquisition of multiple 2D NMR data sets. These new pulse sequences offer an attractive approach for efficient measurement of multiple 2D NMR spectra in a single experiment, enhancing identification and quantitation of metabolites in metabolomics samples. The advantages of 2D NMR have been extended to metabolomics studies with larger sample cohorts.