Dissect and Divide: Putting NMR spectra of mixtures under the knife
Journal: Journal of the American Chemical Society
Publication Date: 19 March, 2019
Department of: Chemistry
British stout dissected with a virtual scalpel
It is hard to overstate the importance of mixture analysis: it underpins progress in most areas of chemistry, biology and pharmacy, and by extension such areas as food safety, security and healthcare. Advances in scientific understanding and economic progress alike depend on our ability to analyse complex mixtures. Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful techniques we have for analysing pure compounds, but it currently struggles with all but the simplest mixtures. In complex mixtures it is often impossible to tell which signals come from which species, so costly separation is needed for analysis. This is frustrating, because NMR, which is non-destructive and non-invasive, has the potential to analyse intact mixtures, without the need for separation.
Researchers in the NMR Methodology Group at the University of Manchester’s School of Chemistry have developed a new NMR method for analyzing complex intact mixtures, demonstrating it by extracting the NMR spectra of individual sugars in stout beer. SCALPEL (Spectral Component Acquisition by Localized PARAFAC Extraction of Linear components) dissects the spectrum rather than the sample, using NMR experiments tailored to generate data suitable for powerful statistical analysis. It represents a step function improvement in our ability to analyse challenging mixtures, and has the potential to tackle problems well beyond the reach of current methods.
- The new method performs a virtual separation of the components of a complex mixture without the need for physical separation
- SCALPEL cuts out one small set of mixture components at a time – hence the name
- PARAFAC (PARAllel FACtor analysis) is a powerful mathematical tool for the statistical analysis of multilinear data
- SCALPEL separates the spectra of mixture components by labelling each component according to the size, motion and structure of its molecules
- Data analysis is straightforward using the NMR Methodology group’s free and open source General NMR Analysis Toolbox (GNAT) software package