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Methods for the SI Value Assignment of the Purity of Organic Compounds (IUPAC Technical Report)



David L. Duewer, Katrice Lippa, Brian Lang, Blaza Toman, Michael Nelson, Kenneth W. Pratt, Steven Westwood, Yoshitaka Yoshitaka Shimuzu, Takeshi Saito, Beatrice Lalerle, Xinhua Dai, Stephen Davies, Marina Ricci, Annarita Baldan, Stefan Sarge, Haifeng Wang, Ralf D. Josephs, Michal Mariassy, Dietmar Pfieffer, John Warren, Wolfram Bremser, Stephen L.R. Ellison, Ting Huang, Ales Fajgelj, Lindsey Mackay, Robert Wielgosz


Metrological traceability to the SI of the result of an analysis for an organic compound is achieved through a calibration hierarchy anchored in a primary calibrator of the compound, the mass fraction content of which is established in a manner traceable within a stated uncertainty to the SI. The source material may be a pure substance Certified Reference Material (CRM) or a laboratory may choose to value assign a pure material with valid methods. The report describes the approach, performance and applicability of the principal methods used to determine organic purity – mass balance, quantitative NMR, thermal methods and other direct assay techniques. A statistical section reviews best practice for combination of data, value assignment as the upper limit values corresponding to 100% purity are reached and how to report and propagate the standard uncertainty associated with the assigned values.
Pure and Applied Chemistry


Organic purity, metrological traceability, measurement uncertainty, Primary Reference Materials, Certified Reference Materials, primary calibrators, mass balance, qNMR, thermal analysis, titrimetry, calibration hierarchy, uncertainty propagation, related structure impurities, water content, volatile organic compounds


Duewer, D. , Lippa, K. , Lang, B. , Toman, B. , Nelson, M. , Pratt, K. , Westwood, S. , Yoshitaka Shimuzu, Y. , Saito, T. , Lalerle, B. , Dai, X. , Davies, S. , Ricci, M. , Baldan, A. , Sarge, S. , Wang, H. , Josephs, R. , Mariassy, M. , Pfieffer, D. , Warren, J. , Bremser, W. , Ellison, S. , Huang, T. , Fajgelj, A. , Mackay, L. and Wielgosz, R. (2023), Methods for the SI Value Assignment of the Purity of Organic Compounds (IUPAC Technical Report), Pure and Applied Chemistry, [online], (Accessed April 19, 2024)
Created January 18, 2023, Updated January 23, 2023