NMR Teaching Strategies in the Instrumental Analysis Laboratory: Identification and Quantification of Caffeine in Energy Drinks

Chemistry undergraduate curricula typically place Nuclear Magnetic Resonance (NMR) lectures under either Organic Chemistry or Spectroscopy courses, aiming for students to acquire basic knowledge for the determination of the structure of simple organic compounds. On the other hand, regarding laboratory practice, NMR is frequently disregarded by Analytical Chemistry or Instrumental Analysis courses, where chromatographic and spectrophotometric methods are the primary analytical techniques taught for the detection and quantification of analytes. However, in recent years, quantitative NMR (qNMR) has been increasingly used for the analysis of natural products, drugs, and foods. Consequently, it would seem advisable to encourage a more active inclusion of NMR in Chemistry courses. One step in that direction is to develop teaching strategies for the laboratory practice, focused on qNMR, that can be featured in the curricula of instrumental analysis courses, to provide students with the essential skills for qNMR practice. Following this logic, an experimental procedure for quantifying caffeine in energy drinks using NMR as an analytical technique, designed to be carried out by students of Analytical Chemistry and Instrumental Analysis courses of chemistry majors, is described below. The pedagogical coverage of this teaching activity, intended for Instrumental Analysis or Analytical Chemistry laboratory courses, includes topics such as solutions and sample preparation with deuterated solvents, NMR instrumentation, NMR data analysis for signal assignment and integration, qNMR concepts, and validation parameters.