Wagner Wollinger, Jane Luiza Nogueira Fernandes, Eliane Cristina Pires do Rego, Francisco Radler de Aquino Neto, Bruno Carius Garrido
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引用次数: 0
Abstract
The Brazilian National Metrology Institute produced a suite of certified reference materials (CRMs) intended as internal standards (ISs) for quantitative nuclear magnetic resonance (qNMR). Being a ratio primary method, the use of qNMR in organic chemistry has already crossed the borders of research laboratories, despite the cost of instrumentation. The International Bureau of Weights and Measures (BIPM) proposed eight potential qNMR ISs. Four candidate materials were selected for their solubility in various solvents and distinct chemical shifts, making them suitable for qNMR analysis of diverse analytes. The certification process compared orthogonal primary methods such as mass balance, qNMR, freezing-point depression, and coulometry, to ensure independent value assignment. Different approaches were compared to assess batch homogeneity and stability. While directly comparing the main compound's chromatographic area proved to be a quick and fit-for-purpose approach, the determination of individual impurities provided lower uncertainties but required more laborious work. CRM batches of maleic acid, dimethyl sulfone, potassium hydrogen phthalate, and dimethyl terephthalate were delivered with over 999.8 mg g-1 purity and uncertainty in the range of 0.6 to 3 mg g-1 (k = 2). The literature shows certification procedures for qNMR ISs whose traceability chain is exclusively based on qNMR measurements. As opposed to that, the methodology presented here provides robust certified values assigned by methods independent of qNMR, in accordance with BIPM recommendations and less prone to qNMR biases. The CRMs developed in this work have already been used for SI-traceable purity evaluation of compounds such as drugs and pesticides, by laboratories in Brazil and abroad.
巴西国家计量研究所生产了一套认证标准物质(CRMs),作为定量核磁共振(qNMR)的内部标准(ISs)。作为一种比率主要方法,qNMR在有机化学中的应用已经跨越了研究实验室的边界,尽管仪器成本很高。国际计量局(International Bureau of Weights and Measures, BIPM)提出了8个潜在的qNMR ISs。选择了四种候选材料,因为它们在各种溶剂中的溶解度和不同的化学位移,使它们适合于各种分析物的qNMR分析。认证过程比较了正交的主要方法,如质量平衡、qNMR、冰点下降和库仑法,以确保独立的值赋值。比较了不同的方法来评估批次的均匀性和稳定性。虽然直接比较主要化合物的色谱面积被证明是一种快速和适合目的的方法,但单个杂质的测定提供了较低的不确定度,但需要更费力的工作。CRM批次的马来酸、二甲基砜、邻苯二甲酸氢钾和对苯二甲酸二甲酯的纯度超过999.8 mg g-1,不确定度范围为0.6至3mg g-1 (k = 2)。文献显示了qNMR ISs的认证程序,其可追溯链完全基于qNMR测量。与此相反,本文提出的方法提供了由独立于qNMR的方法分配的可靠认证值,符合BIPM建议,不容易受到qNMR偏差的影响。在这项工作中开发的crm已经被巴西和国外的实验室用于药物和农药等化合物的si可追溯纯度评估。
期刊介绍:
Analytical and Bioanalytical Chemistry’s mission is the rapid publication of excellent and high-impact research articles on fundamental and applied topics of analytical and bioanalytical measurement science. Its scope is broad, and ranges from novel measurement platforms and their characterization to multidisciplinary approaches that effectively address important scientific problems. The Editors encourage submissions presenting innovative analytical research in concept, instrumentation, methods, and/or applications, including: mass spectrometry, spectroscopy, and electroanalysis; advanced separations; analytical strategies in “-omics” and imaging, bioanalysis, and sampling; miniaturized devices, medical diagnostics, sensors; analytical characterization of nano- and biomaterials; chemometrics and advanced data analysis.