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Westwood S, Lippa K, Shimuzu Y, Lalerle B, Saito T, Duewer D, Dai X, Davies S, Ricci M, Baldan A, Lang B, Sarge S, Wang H, Pratt K, Josephs R, Mariassy M, Pfeifer D, Warren J, Bremser W, Ellison S, Toman B, Nelson M, Huang T, Fajgelj A, Gören A, Mackay L, Wielgosz R. Methods for the SI-traceable value assignment of the purity of organic compounds (IUPAC Technical Report). PURE APPL CHEM 2023. [DOI: 10.1515/pac-2020-0804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Abstract
The “purity” of an organic compound typically refers, in practice, to an assignment of the mass fraction content of the primary organic component present in the material. The “purity” value of an organic primary calibrator material is the ultimate source of metrological traceability of any quantitative measurement of the content of that compound in a given matrix. The primary calibrator may consist of a Certified Reference Material (CRM) whose purity has been assigned by the CRM producer or a laboratory may choose to value-assign a material to the extent necessary for their intended application by using appropriately valid methods. This report provides an overview of the approach, performance and applicability of the principal methods used to determine organic purity including mass balance, quantitative NMR, thermal methods and 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 approached and how to report and propagate the standard uncertainty associated with the assigned values.
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Affiliation(s)
- Steven Westwood
- Bureau International des Poids et Mesures (BIPM) , Sèvres , France
| | - Katrice Lippa
- National Institute of Standards and Technology (NIST) , Gaithersburg , MD , USA
| | | | - Beatrice Lalerle
- Laboratoire Nationale de Métrologie et d’Essais (LNE) , Paris , France
| | - Takeshi Saito
- National Metrology Institute of Japan (NMIJ) , Tsukuba , Japan
| | - David Duewer
- National Institute of Standards and Technology (NIST) , Gaithersburg , MD , USA
| | - Xinhua Dai
- National Institute of Metrology (China) (NIM) , Beijing , China
| | - Stephen Davies
- National Measurement Institute Australia (NMIA) , North Ryde , NSW , Australia
| | | | - Annarita Baldan
- Nederlands Metrologisch Instituut (VSL) , Delft , The Netherlands
| | - Brian Lang
- National Institute of Standards and Technology (NIST) , Gaithersburg , MD , USA
| | - Stefan Sarge
- Physikalisch-Technische Bundesanstalt (PTB) , Braunschweig , Germany
| | - Haifeng Wang
- National Institute of Metrology (China) (NIM) , Beijing , China
| | - Ken Pratt
- National Institute of Standards and Technology (NIST) , Gaithersburg , MD , USA
| | - Ralf Josephs
- Bureau International des Poids et Mesures (BIPM) , Sèvres , France
| | | | - Dietmar Pfeifer
- Bundesanstalt für Materialforschung und -Prüfung (BAM) , Berlin , Germany
| | | | - Wolfram Bremser
- Bundesanstalt für Materialforschung und -Prüfung (BAM) , Berlin , Germany
| | | | - Blaza Toman
- National Institute of Standards and Technology (NIST) , Gaithersburg , MD , USA
| | - Michael Nelson
- National Institute of Standards and Technology (NIST) , Gaithersburg , MD , USA
| | - Ting Huang
- National Institute of Metrology (China) (NIM) , Beijing , China
| | - Ales Fajgelj
- International Atomic Energy Agency , Vienna , Austria
| | - Ahmet Gören
- Kimya Bölümü, Gebze Teknik Üniversitesi , Gebze , Turkey
| | - Lindsey Mackay
- National Measurement Institute Australia (NMIA) , North Ryde , NSW , Australia
| | - Robert Wielgosz
- Bureau International des Poids et Mesures (BIPM) , Sèvres , France
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Neves LA, Rodrigues JM, Daroda RJ, Silva PRM, Ferreira AA, Aranda DAG, Eberlin MN, Fasciotti M. The influence of different referencing methods on the accuracy of δ(13) C value measurement of ethanol fuel by gas chromatography/combustion/isotope ratio mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2015; 29:1938-1946. [PMID: 26443391 DOI: 10.1002/rcm.7298] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Revised: 07/30/2015] [Accepted: 07/31/2015] [Indexed: 06/05/2023]
Abstract
RATIONALE Brazil is the largest producer of sugar cane bioethanol in the world. Isotope ratio mass spectrometry (IRMS) is the technique of choice to certify the origin/raw materials for ethanol production, but the lack of certified reference materials (CRMs) for accurate measurements of δ(13) C values traceable to Vienna Pee Dee Belemnite (VPDB), the international zero point for (13) C/(12) C measurements, certified and compatible with gas chromatography (GC)/IRMS instruments may compromise the accuracy of δ(13) C determinations. METHODS We evaluated the influence of methods for the calibration and normalization of raw δ(13) C values of ethanol samples. Samples were analyzed by GC/C/IRMS using two different GC columns. Different substances were used as isotopic standards for the working gas calibration. The δ(13) C values obtained with the three methods of normalization were statistically compared with those obtained with elemental analyzer (EA)/IRMS, since the δ(13) C results obtained using EA are traceable to VPDB via the NBS 22 reference material. RESULTS It was observed that both the isotopic reference material for CO2 calibration and the GC column have a major effect on the δ(13) C measurements, leading to a bias of almost 2-3 ‰ in the δ(13) C values. All three methods of normalization were equivalent in performance, enabling an improvement in the GC/C/IRMS accuracy, compared with the EA/IRMS reference values for the samples. CONCLUSIONS All the methods of CO2 calibration, chromatography and normalization presented in this work demonstrated several sources of traceability and accuracy loss for the determination of δ(13) C values in ethanol fuel samples by GC/C/IRMS. This work has also shown the importance of using proper CRMs traceable to VPBD that should be compatible and certified using GC/C/IRMS, ideally in a wide range of δ(13) C values. This is important not only for bioethanol fuel samples, but also for many analytes commonly analyzed by IRMS.
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Affiliation(s)
- Laura A Neves
- National Institute of Metrology, Quality and Technology -INMETRO, Division of Chemical Metrology, 25250-020, Duque de Caxias, RJ, Brazil
- Laboratory of Green Technologies - GREENTEC, School of Chemistry, Federal University of Rio de Janeiro (UFRJ), Technology Center, 21941-909, Rio de Janeiro, RJ, Brazil
| | - Janaína M Rodrigues
- National Institute of Metrology, Quality and Technology -INMETRO, Division of Chemical Metrology, 25250-020, Duque de Caxias, RJ, Brazil
| | - Romeu J Daroda
- National Institute of Metrology, Quality and Technology -INMETRO, Division of Chemical Metrology, 25250-020, Duque de Caxias, RJ, Brazil
| | - Paulo R M Silva
- National Institute of Metrology, Quality and Technology -INMETRO, Division of Chemical Metrology, 25250-020, Duque de Caxias, RJ, Brazil
| | - Alexandre A Ferreira
- PETROBRAS Research and Development Center - CENPES, Division of Geochemistry, 21941-915, Ilha do Fundão, Rio de Janeiro, RJ, Brazil
| | - Donato A G Aranda
- Laboratory of Green Technologies - GREENTEC, School of Chemistry, Federal University of Rio de Janeiro (UFRJ), Technology Center, 21941-909, Rio de Janeiro, RJ, Brazil
| | - Marcos N Eberlin
- National Institute of Metrology, Quality and Technology -INMETRO, Division of Chemical Metrology, 25250-020, Duque de Caxias, RJ, Brazil
- ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas - UNICAMP, 13083-970, Campinas, SP, Brazil
| | - Maíra Fasciotti
- National Institute of Metrology, Quality and Technology -INMETRO, Division of Chemical Metrology, 25250-020, Duque de Caxias, RJ, Brazil
- ThoMSon Mass Spectrometry Laboratory, Institute of Chemistry, University of Campinas - UNICAMP, 13083-970, Campinas, SP, Brazil
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Davies SR, Alamgir M, Chan BKH, Dang T, Jones K, Krishnaswami M, Luo Y, Mitchell PSR, Moawad M, Swan H, Tarrant GJ. The development of an efficient mass balance approach for the purity assignment of organic calibration standards. Anal Bioanal Chem 2015; 407:7983-93. [PMID: 26342310 DOI: 10.1007/s00216-015-8971-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 08/05/2015] [Accepted: 08/08/2015] [Indexed: 10/23/2022]
Abstract
The purity determination of organic calibration standards using the traditional mass balance approach is described. Demonstrated examples highlight the potential for bias in each measurement and the need to implement an approach that provides a cross-check for each result, affording fit for purpose purity values in a timely and cost-effective manner. Chromatographic techniques such as gas chromatography with flame ionisation detection (GC-FID) and high-performance liquid chromatography with UV detection (HPLC-UV), combined with mass and NMR spectroscopy, provide a detailed impurity profile allowing an efficient conversion of chromatographic peak areas into relative mass fractions, generally avoiding the need to calibrate each impurity present. For samples analysed by GC-FID, a conservative measurement uncertainty budget is described, including a component to cover potential variations in the response of each unidentified impurity. An alternative approach is also detailed in which extensive purification eliminates the detector response factor issue, facilitating the certification of a super-pure calibration standard which can be used to quantify the main component in less-pure candidate materials. This latter approach is particularly useful when applying HPLC analysis with UV detection. Key to the success of this approach is the application of both qualitative and quantitative (1)H NMR spectroscopy.
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Affiliation(s)
- Stephen R Davies
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia.
| | - Mahiuddin Alamgir
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Benjamin K H Chan
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Thao Dang
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Kai Jones
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Maya Krishnaswami
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Yawen Luo
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Peter S R Mitchell
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Michael Moawad
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Hilton Swan
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
| | - Greg J Tarrant
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, New South Wales, 1670, Australia
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Davies SR, Jones K, Goldys A, Alamgir M, Chan BKH, Elgindy C, Mitchell PSR, Tarrant GJ, Krishnaswami MR, Luo Y, Moawad M, Lawes D, Hook JM. Purity assessment of organic calibration standards using a combination of quantitative NMR and mass balance. Anal Bioanal Chem 2014; 407:3103-13. [PMID: 24948087 DOI: 10.1007/s00216-014-7893-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/09/2014] [Accepted: 05/13/2014] [Indexed: 11/29/2022]
Abstract
Quantitative NMR spectroscopy (qNMR) has been examined for purity assessment using a range of organic calibration standards of varying structural complexities, certified using the traditional mass balance approach. Demonstrated equivalence between the two independent purity values confirmed the accuracy of qNMR and highlighted the benefit of using both methods in tandem to minimise the potential for hidden bias, thereby conferring greater confidence in the overall purity assessment. A comprehensive approach to purity assessment is detailed, utilising, where appropriate, multiple peaks in the qNMR spectrum, chosen on the basis of scientific reason and statistical analysis. Two examples are presented in which differences between the purity assignment by qNMR and mass balance are addressed in different ways depending on the requirement of the end user, affording fit-for-purpose calibration standards in a cost-effective manner.
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Affiliation(s)
- Stephen R Davies
- Chemical Reference Materials, National Measurement Institute, P.O. Box 138, North Ryde, NSW, 1670, Australia
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The importance of reference materials in doping-control analysis. Anal Bioanal Chem 2011; 401:483-92. [DOI: 10.1007/s00216-011-5049-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2011] [Revised: 04/16/2011] [Accepted: 04/20/2011] [Indexed: 10/18/2022]
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Yip YC, Wong SK, Choi SM. Assessment of the chemical and enantiomeric purity of organic reference materials. Trends Analyt Chem 2011. [DOI: 10.1016/j.trac.2010.12.003] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Lott S, Henrion A, Malz F, Kessler A, Güttler B, Aderjan R. Reference measurement procedure for Δ9-tetrahydrocannabinol in serum. Anal Bioanal Chem 2008; 391:1003-10. [DOI: 10.1007/s00216-008-2065-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Revised: 03/04/2008] [Accepted: 03/10/2008] [Indexed: 11/30/2022]
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Burns M. Current practice in the assessment and control of measurement uncertainty in bio-analytical chemistry. Trends Analyt Chem 2004. [DOI: 10.1016/s0165-9936(04)00523-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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