Reference and normalization methods: Essential tools for the intercomparison of NMR spectra

This review aims at providing an analysis of the various available reference methods in nuclear magnetic resonance, based on recent literature. This paper will provide a tool to help users in choosing the appropriate method depending on the NMR experiment, sample and targeted application. For each method, the crucial parameters that should be particularly considered to reach the accuracy objectives of quantitative NMR are described. After defining the main concepts, the principle, the analytical performance and the main recent applications of each method are described, and a critical discussion is finally provided.