biostudies-literatureNishizaki YNCCIH NIH HHSNational Center for Complementary and Integrative HealthJapan Food Chemical Research Foundation2733-2741https://www.ebi.ac.uk/biostudies/studies/S-EPMC8046598biostudies-literatureUnknown93(5)Quantitative ¹H nuclear magnetic resonance (qHNMR) is a highly regarded analytical methodology for purity determination as it balances metrological rigor, practicality, and versatility well. While ideal for intrinsically mass-limited samples, external calibration (EC) qHNMR is overshadowed by the prevalence of internal calibration and perceived rather than real practical limitations. To overcome this hurdle, this study applied the principle of reciprocity, certified reference materials (caffeine as analyte, dimethyl sulfone as calibrant), and a systematic evaluation of data acquisition workflows to extract key factors for the achievement of accuracy and precision in EC-qHNMR. Automatic calibration of the 90° pulse width (90 PW) formed the foundation for the principle of reciprocAnalytical chemistryAccurate and Precise External Calibration Enhances the Versatility of Quantitative NMR (qNMR).PMC8046598U41AT008706U41 AT008706Chen SNLankin DCNishizaki YPauli GFfalseAccurate and Precise External Calibration Enhances the Versatility of Quantitative NMR (qNMR).Quantitative ¹H nuclear magnetic resonance (qHNMR) is a highly regarded analytical methodology for purity determination as it balances metrological rigor, practicality, and versatility well. While ideal for intrinsically mass-limited samples, external calibration (EC) qHNMR is overshadowed by the prevalence of internal calibration and perceived rather than real practical limitations. To overcome this hurdle, this study applied the principle of reciprocity, certified reference materials (caffeine as analyte, dimethyl sulfone as calibrant), and a systematic evaluation of data acquisition workflows to extract key factors for the achievement of accuracy and precision in EC-qHNMR. Automatic calibration of the 90° pulse width (90 PW) formed the foundation for the principle of reciproc2021-01-01T00:00:00Z2021 Feb2026-05-30T16:48:09.006Z2025-04-04T10:02:29.082ZS-EPMC80465983348157110.1021/acs.analchem.0c02967