Development of nuclear magnetic resonance as a tool of quantitative analysis for organic materials

It has been recognized for a long time that nuclear magnetic resonance (NMR) spectroscopy can be used for quantification; the resonance peak area is known to be proportional to the number of nuclei contributing to the peak. However, quantification by Fourier transformation (FT) NMR was believed to be only accurate to within a few percent to 10%, and in general, analytical chemists thought the level of accuracy was not satisfactory. However, about 20 years ago, chemical metrologists began to recognize the usefulness of quantitative applications of NMR for determining the purity of organic materials. Here, we present a brief review on purity assessment of the quantitative NMR (qNMR) and its contribution to the consultative committee for amount of substance: metrology in chemistry and biology (CCQM) working group on organic analysis (OAWG).