Extremely accurate and precise quantitative NMR was demonstrated using the new qNMR tools in VnmrJ 3.1 software and calibration with an external standard. Periodic calibration can deliver accuracy as high as 99.9% and precision as good as 0.59%, while performing calibration with each study can result in accuracy and precision as high as 100% and 0.35%, respectively.
While used most often for structural analysis, NMR is most powerful when used quantitatively, as the integrated intensity of a resonance signal is directly proportional to the number of nuclei represented by that signal. In addition, all protons across the spectrum are equally sensitive, so determination of quantitative results does not require the need for compound-speci c extinction coef cients or calibrations. NMR has been used to determine concentrations of synthetic and biosynthetic products, ne chemicals, and pharmaceuticals, as well as metabolites, catabolites, and endog- enous compounds in biological uids1. Quantitative NMR (qNMR) has been shown to be particularly useful in metabolomics, drug discovery and analysis, and natural product analysis2.