By Eriks Kupce
Structure elucidation and characterization of small molecules by NMR largely follows well-establishedprotocols that rely on a core set of 2D correlation experiments such as COSY, TOCSY, NOESY, ROESY,HSQC, HMBC, ADEQUATE or INADEQUATE. We show that up to 10 such experiments can be combinedinto a single entity called a supersequence [1,2]. This leads to a dramatic reduction of data collection timeand significant improvements in sensitivity of NMR measurements. Such supersequences can be tailoredfor specific applications, for instance, the analysis and characterization of molecular structure of complexorganic molecules. When combined with computer assisted structure elucidation (CASE) software such asCASPER, structure of oligosaccharides can be established from a single measurement with a high degreeof confidence. Likewise, 2D NMR-based metabolomics with sensitivity improved versions of HSQC/TOCSYNOAH supersequences allow efficient measurement of multiple 2D NMR spectra (HSQCsi and/orHSQCsi−TOCSY and TOCSY) of metabolomics samples in a single experiment for the accurate andcomprehensive identification and quantitation of metabolites. Involving multiple receiver technologyopens new avenues for multiplexing NMR experiments thus reducing the cost of NMR analysis,increasing sensitivity and the information content of NMR measurements [3,4].We shall discuss the design principles of such super sequences.
References1. Ē. Kupče and R. Freeman, Molecular Structure from a Single NMR Experiment, J. Am. Chem. Soc.,130, 10788–10792 (2008).2. Ē. Kupče and T. D. W. Claridge, NOAH: NMR Supersequences for Small Molecule Analysis and StructureElucidation, Angew. Chem. Int. Ed. Eng., 56, 11779-11783 (2017).3. Ē. Kupče, K. R. Mote, A. Webb, P. K. Madhu, T. D.W. Claridge, Multiplexing experiments in NMR andmulti-nuclear MRI, Prog. NMR Spectrosc., 124-125, 1-56 (2021).4. Ē. Kupče, L. Frydman, A. G. Webb, J. Yong, and T. Claridge, Parallel nuclear magnetic resonancespectroscopy, Nature Reviews Methods Primers, 1, 27 (2021).