TY - CONF A1 - Maiwald, Michael T1 - qNMR metrology and current "primary" reference material activities N2 - In general, most quantitative organic chemical measurements rely on the availability of highly purified compounds to act as calibration standards. The traceability and providence of these standards is an essential component of any measurement uncertainty budget and provides the final link of the result to the units of measurement, ideally the SI. The more recent increase in the use of qNMR for the direct assessment of chemical purity however can potentially improve the traceability and reduce the uncertainty of the measured chemical purity at a reduced cost and with less material. For example, the method has beneficially been used by National Metrology Institutes for comparisons including comparisons on CCQM (Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology, www.bipm.org). First comparisons started 1998 with CCQM-P3 (Organics in solution) or CCQM-P35 (2002, EtOH in solution), were underpinned by a broad range of polarity and molecular size (CCQM–K55 series of purity studies including Valine, Aldrin, or Folic acid) and were continued with the recent pilot studies CCQM-P150 (2014, purity of Dimethyl sulfone) or CCQM-P150b (2017, purity of Pyributicarb). Traditional ‘indirect’ methods of purity analysis require that all impurities are identified and quantified, leading to a minimum of four individual analytical methods (organic impurities, water, solvents, inorganic residue). These multiple technique approaches measure an array of different chemical impurities normally present in purified organic chemical compounds. As many analytical methodologies have compound-specific response factors, the accuracy and traceability of the purity assessment is dependent on the availability of reference materials of the impurities being available. qNMR provides the most universally applicable form of direct purity determination without need for reference materials of impurities or the calculation of response factors but only exhibiting suitable NMR properties. The development of CRMs addressing qNMR specific measurement issues will give analysts compounds ideally suited for the analytical method and also provide full characterisation of qNMR related parameters to enable more realistic uncertainty budgets. These materials will give users the tools to exploit qNMR more easily and enable them to speed up analytical method development and reduce the time and financial burden of multiple analytical testing. Due to recent advances in technical developments of NMR instruments such as acquisition electronics and probe design, detection limits of components in liquid mixtures were improved into the lower ppm range (approx. 5–10 ppm amount of substance) qNMR studies increasingly attract broader interest. T2 - qNMR Day CY - Politecnico di Bari, Bari, Italy DA - 24.11.2017 KW - qNMR KW - Quantitative NMR spectroscopy KW - qNMR metrology KW - Primary reference material KW - Comparison study KW - Direct purity determination PY - 2017 UR - http://www.gidrm.org/index.php/activities/workshops/2017-workshops/qnmr-day-a-gidrm-organized-in-cooperation-with-girm AN - OPUS4-43119 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -