Guide to NMR Method Development and Validation – Part I: Identification and Quantification

Nuclear Magnetic Resonance (NMR) spectroscopy is one of the most versatile methods of analysis. Till the early 1970s, NMR spectroscopy was exclusively used for structure elucidation and purity testing of synthesized compounds. Nowadays, however, the range of successful applications covers identification and structure elucidation of organic and biochemical molecules, precise quantitative determination of individual analytes and multicomponent analysis as well as so-called "non-targeted screening" in combination with different chemometric techniques [1, 2]. Since NMR is a very selective analytical tool (each molecule has its own spectral fingerprint), not only quantification of ingredients is possible, but also comparison, discrimination or classification of foods, beverages and other consumer products can be achieved (e.g., authenticity evaluation, determination of origin and botanical variety of certain products) [1]. "Non-targeted" NMR analysis allows a fast and highly selective sample screening, from which much more information can be obtained than by using any other analysis technique that was previously used for this purpose [1]. NMR techniques have been an integral part of scientific research for a long time and are increasingly used in the monitoring of foods, beverages, cosmetics and pharmaceuticals. The special criteria proposed in this report should facilitate development of any practical application of a NMR method in these areas of applications. Furthermore, our suggestions are in accordance with quality management (QM) system required for governmental food control [3-5]. It should be mentioned, however, that the conditions listed in this report must always be adapted for the specific analytical problem, the most recent QM requirement and the matrix under investigation.