Quantitative and non targeted NMR approaches in metrological traceability

NMR spectroscopy is gaining increasing importance in analytical chemistry. In the last decade, quantitative NMR (qNMR) and untargeted approaches have enabled great improvements in both the quantification of molecules in complex mixtures and the identification of product characteristics in suitable sample pools. Metrological traceability of products can be successfully achieved by qNMR even when certified reference materials are not commercially available. Along with the quantification and purity assessment of molecules, NMR is also emerging as a powerful tool in food chemistry, especially when looking for product characteristics such as cultivar, geographical origin, typicality of the production process, etc. The great application potential of NMR spectroscopy arises from the fact that, according to theory, the ratio of a signal generated by the molecule under investigation to the signal of a reference molecule depends exclusively on the corresponding molar ratio. In other words, when a given sample is analyzed by different spectrometers, the same output in terms of signal ratios is obtained regardless of the hardware configuration. This offers a unique opportunity to develop analytical systems capable of identifying sample characteristics and quantifying several molecules 1,2,3. In particular, the case study of both the identification of wheat and pasta samples and the quantification of betaine will be presented. The advantages and limitations of using non targeted NMR analyses performed at different magnetic fields will also be discussed.