Nuclear magnetic resonance spectroscopy of fluorine-19 nucleus (19F-NMR) emerges as a powerful tool because of the high sensitivity due to its high natural abundance, broad spectral range, and the simplicity of a spin-half system. However, it is still seldom utilized in the chemistry classroom or research. This article thus aims to demonstrate the power of NMR by investigating the kinetics when a 19F-tag reacts with individual amino acids (AA) and eventually utilizing the approach to identify and quantify various AAs from a complex mixture such as a metabolomics sample. The 19F-tag named 2,5-dioxopyrrolidin-1-yl-2-(trifluoromethyl)benzoate was synthesized following a previously established method. The reaction kinetics of the tag was then continuously measured using 19F NMR in the presence of selected AAs. The estimated reaction rate constants to form the 19F-tags with each AA differ, which could be used as an identification tool. The tag formations were typically completed in 24–48 h in water for all the samples. These demonstrations suggest that 19F-tags could form the basis for chemical kinetics and AA detection using 19F-NMR.