The BIPM has published the first set of reference data to support laboratories world-wide that use quantitative Nuclear Magnetic Resonance (qNMR) for the purity assignment of organic compounds, thereby aiding the development of primary reference materials for SI traceable calibration hierarchies in organic analysis as well as Reference Standards and assays for pharmaceutical laboratories. The document was developed as part of a BIPM-NMIJ (Japan) collaboration together with visiting scientists from NIM (China), INMETRO (Brazil) and UME (Turkey) at the BIPM.
The online publication of the first Internal Standard Reference Data (ISRD) document is for the use of maleic acid as a qNMR internal standard. The ISRD provides specific guidance on the use and limitations of maleic acid and general recommendations for experimental design, treatment of data and assignment of measurement uncertainty from a quantitative 1H NMR measurement.
The publication on maleic acid is the first of seven documents covering a set of 7 "universal calibrators" for qNMR, identified by the NMIJ and the BIPM as being able to serve as an ensemble of internal standards that would enable purity assignment measurements by qNMR of the vast majority of organic analyte/solvent combinations.
The full set of seven standards that make up the qNMR universal calibrator set are: maleic acid (MA) [ISRD-01]; dimethyl sulfone (DMSO2) [ISRD-02]; potassium hydrogen phthalate (KHP) [ISRD-03]; 3,5-bistrifluoromethyl benzoic acid (BTFMBA) [ISRD-04]; dimethyl terephthalate (DMTP) [ISRD-05]; 1,4-bistrimethylsilylbenzene (BTMSB) [ISRD-06]; 3-trimethylsilyl propanesulfonic acid sodium salt-d6 (DSS-d6) [ISRD-07].
The development and publication of the ISRD document was presented by the BIPM during an invited lecture on the "Role and Use of Reference Materials to underpin SI-Traceable measurements for qNMR" at the qNMR Summit 2018 held recently in Tokyo.
The event was organized under the auspices of a Japanese Ministry of Economy, Trade and Industry initiative to promote "international standardization development activities", with representatives of National Metrology Institutes, pharmacopeias, certified reference materials producers and industry.
More than two hundred participants attended over the two days of the summit sessions, which featured national and international experts in qNMR. It focused on recent advances in the use, applications and benchmarking of NMR and qNMR in academic research, industrial process control, pharmaceutical manufacturing and drug development.