Recent advances in ratio primary reference measurement procedures (definitive methods) and their use in certification of reference materials and controlling assigned values in proficiency testing

The paper considers the contribution of experts from the Laboratory of Metrology of Moisture Measurement and Reference Materials to the improvement of the food industry metrological assurance system. The information on the results of the development of forty types of reference materials (RM) for the composition of various nutrition, food staples and nutritional supplement in the period 2008-2020 is generalized. The development of each new RM type included preparation of the material, research for its stability and homogeneity, and determination of certified value with the appliance of State primary (GET 173) and secondary (GVET 176-1) standards, as well as primary reference measurement procedures and conducting the interlaboratory experiment for checking the applicability of the RM. The creation in 2008 of GET 173 was accompanied by the development of RMs for the composition of grains and dry milk product. The approval in 2010 of GVET 176-1 allowed to add in the RM the certified value for the mass fraction of nitrogen (protein). As a result of successful participation in comparisons, UNIIM got 6 items of calibration and measurement capabilities on measurements of mass fraction of nitrogen in glycine, milk powder, grain, egg powder, cereal and feed-stuff in the BIPM database. 35 types of RM for the composition of dairy and meat products, egg powder, infant food, oil and starch products together with the development of primary reference measurement procedures for measurement of fat, crude fat, ash and carbohydrates mass fraction were created between 2016 and 2019. Moreover, the RM for the composition of nutritional supplement (glycine, melamine, cystine) and dairy products for metrological assurance of IR-analysers as well as RM for the composition of reconstituted milk were developed for the control of measurement results by the enzyme-linked immunosorbent assay (ELISA). Developed RM were systemized on fields of the appliance of Technical regulations of Customs Union and the sectors of the international food triangle model. These RMs allow providing the measurement uniformity of the identification indicators and the nutritional value of food products and food staples.

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Preparation of Three New Certified Reference Materials for Food and Environmental Analysis and Certification Using Laboratory Intercomparison as well as Primary Reference Measurement Procedures

Food Analytical Methods ◽

10.1007/s12161-021-02081-6 ◽

2021 ◽

Author(s):

Halina Polkowska-Motrenko ◽

Zbigniew Samczyński ◽

Rajmund S. Dybczyński ◽

Ewelina Chajduk ◽

Bożena Danko ◽

...

Keyword(s):

Mass Spectrometry ◽

Reference Materials ◽

Trace Analysis ◽

Inductively Coupled Plasma ◽

Certified Reference Materials ◽

Isotope Dilution Mass Spectrometry ◽

Analytical Techniques ◽

Reference Measurement ◽

Certification Procedure ◽

Primary Reference

AbstractThree new reference materials: MODAS-3 Herring Tissue (M-3 HerTis), MODAS-4 Cormorant Tissue (M-4 CormTis), and MODAS-5 Cod Tissue (M-5 CodTis) were prepared and certified on the basis of results of a worldwide intercomparison exercise. Independently of our proven method of establishing the certified and information values, the content of several essential and toxic elements was additionally determined by the use of ratio primary reference measurement procedures (definitive methods) based on radiochemical neutron activation analysis (RNAA) in the case of As, Cd, Co, Cr, Fe, Mo, Se, and U and isotope dilution mass spectrometry (IDMS) in the case of Hg, respectively. Good agreement of the established certified values and the results obtained by ratio primary reference measurement procedures confirmed the validity of the certification procedure. The total number of elements which could be certified amounted to 30, 21, 18 in M-3 HerTis, M-4 CormTis, and M-5 CodTis, respectively. The relative frequency of use of individual analytical techniques in this intercomparison campaign was calculated and discussed. Inductively coupled plasma mass spectrometry (ICP-MS) is now a dominant technique, followed by atomic absorption spectroscopy (AAS), NAA, and emission spectroscopy (ES). The decreasing share of NAA as compared to several earlier intercomparison exercises should be noticed. NAA is the only method in the array of highly sensitive methods of inorganic trace analysis, which is essentially free from blank. The lack of this method in the foreseeable future may be an obstacle in the prospective certification campaigns and may endanger the implementation of quality assurance in trace analysis.

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Primary Reference Materials

Charles Ives ◽

10.4324/9780203890509-7 ◽

2010 ◽

pp. 21-29

Keyword(s):

Reference Materials ◽

Primary Reference

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Development of primary reference measurement procedures for food quality control

Journal of Physics Conference Series ◽

10.1088/1742-6596/1420/1/012006 ◽

2019 ◽

Vol 1420 ◽

pp. 012006

Author(s):

Sergey V Medvedevskikh ◽

Maria Y Medvedevskikh ◽

Anna S Sergeeva ◽

Vasilisa B. Baranovskaya

Keyword(s):

Quality Control ◽

Food Quality ◽

Reference Measurement ◽

Food Quality Control ◽

Primary Reference

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Laboratory Accreditation: Standards, Reference Materials and Proficiency Testing

Harmonisation of Testing Practice for High Temperature Materials ◽

10.1007/978-94-011-2888-9_4 ◽

1992 ◽

pp. 53-65 ◽

Cited By ~ 1

Author(s):

Peter Van De Leemput

Keyword(s):

Proficiency Testing ◽

Reference Materials ◽

Laboratory Accreditation ◽

Accreditation Standards

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Experience with Certified Reference Material Proficiency Testing for Quality Control of Wheat

Journal of Near Infrared Spectroscopy ◽

10.1255/jnirs.166 ◽

1998 ◽

Vol 6 (A) ◽

pp. A53-A61

Author(s):

Judit Budai ◽

Judit Fükó

Keyword(s):

Quality Control ◽

Reference Material ◽

Proficiency Testing ◽

Reference Materials ◽

Certified Reference Material ◽

Certified Reference Materials ◽

Long Term Stability ◽

Determining Factors ◽

Chemical Section

The Chemical Section of OMH1,2 embarked on the preparation of a series of wheat samples as Certified Reference Materials (CRMs) in 1992. The certification processes were carried out according to the recommendations of ISO. Since then we have developed a series of flour samples as well. The investigations of the long-term stability and the application of wheat and flour CRMs are continuous. Wheat is one of the most widely grown crops in Hungary and it is one of the major determining factors of the economy. Its uniform and objective qualification is of great importance. There are well-equipped laboratories available with sufficient experience but, as the proficiency testing regularly showed, certified samples need to be used to achieve exact and uniform measuring results.

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Acute and chronic canine ex vivo blood interactions with NHLBI-DTB Primary Reference Materials

Biomaterials ◽

10.1016/0142-9612(89)90100-2 ◽

1989 ◽

Vol 10 (4) ◽

pp. 243-250 ◽

Cited By ~ 8

Author(s):

Timothy J. McCoy ◽

Timothy G. Grasel ◽

Ann Z. Okkema ◽

Stuart L. Cooper

Keyword(s):

Reference Materials ◽

Ex Vivo ◽

Primary Reference

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Assessment of Digital PCR as a Primary Reference Measurement Procedure to Support Advances in Precision Medicine

Clinical Chemistry ◽

10.1373/clinchem.2017.285478 ◽

2018 ◽

Vol 64 (9) ◽

pp. 1296-1307 ◽

Cited By ~ 18

Author(s):

Alexandra S Whale ◽

Gerwyn M Jones ◽

Jernej Pavšič ◽

Tanja Dreo ◽

Nicholas Redshaw ◽

...

Keyword(s):

Precision Medicine ◽

Copy Number ◽

Digital Pcr ◽

Measurement Procedure ◽

Patient Treatment ◽

Molecular Diagnostic ◽

Reference Measurement ◽

Reference Measurement Procedure ◽

Wide Range ◽

Primary Reference

Abstract BACKGROUND Genetic testing of tumor tissue and circulating cell-free DNA for somatic variants guides patient treatment of many cancers. Such measurements will be fundamental in the future support of precision medicine. However, there are currently no primary reference measurement procedures available for nucleic acid quantification that would support translation of tests for circulating tumor DNA into routine use. METHODS We assessed the accuracy of digital PCR (dPCR) for copy number quantification of a frequently occurring single-nucleotide variant in colorectal cancer (KRAS c.35G>A, p.Gly12Asp, from hereon termed G12D) by evaluating potential sources of uncertainty that influence dPCR measurement. RESULTS Concentration values for samples of KRAS G12D and wild-type plasmid templates varied by <1.2-fold when measured using 5 different assays with varying detection chemistry (hydrolysis, scorpion probes, and intercalating dyes) and <1.3-fold with 4 commercial dPCR platforms. Measurement trueness of a selected dPCR assay and platform was validated by comparison with an orthogonal method (inductively coupled plasma mass spectrometry). The candidate dPCR reference measurement procedure showed linear quantification over a wide range of copies per reaction and high repeatability and interlaboratory reproducibility (CV, 2%–8% and 5%–10%, respectively). CONCLUSIONS This work validates dPCR as an SI-traceable reference measurement procedure based on enumeration and demonstrates how it can be applied for assignment of copy number concentration and fractional abundance values to DNA reference materials in an aqueous solution. High-accuracy measurements using dPCR will support the implementation and traceable standardization of molecular diagnostic procedures needed for advancements in precision medicine.

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