Assessment of methods of assigning certified values to reference materials

Abstract A dry ashing, flameless atomic absorption spectrometric method was evaluated to determine arsenic and selenium in foods. Samples were dry-ashed with Mg(N03)2-MgO and dissolved in HC1. Selenate was reduced to selenite by boiling in 4N HC1, and arsenate to arsenite by treatment with KI. Hydrides of arsenic and selenium were generated by the addition of NaBH4 and were swept by nitrogen and hydrogen into a thermally heated silicate tube furnace. The detection limit was about 5 ppb for each element based on a 10 g sample. Analytical results obtained for several samples of NBS reference materials agreed with the certified values. The procedure was evaluated by another laboratory and results were satisfactory.

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Application of the lyophilization system for preparation of reference materials for composition of nutrition products

Reference materials ◽

10.20915/2687-0886-2021-17-1-35-45 ◽

2021 ◽

Vol 17 (1) ◽

pp. 35-45

Author(s):

M. Y. Medvedevskikh ◽

N. L. Vostrikova ◽

A. S. Sergeeva ◽

V. V. Studenok

Keyword(s):

Reference Materials ◽

Fat Mass ◽

Mass Fraction ◽

Primary Standard ◽

Poultry Meat ◽

Chicken Breast ◽

Homogeneous Material ◽

Freeze Dried ◽

Air Dryer ◽

Certified Values

The article presents the application of the lyophilization system for preparation of reference materials (RM) for composition of nutritive products samples. The purpose of the research was the development of lyophilization procedure of RM for composition of poultry meat samples preparation with certified values of mass fraction of moisture, nitrogen (protein) and fat.The poultry meat of two types was used as the primary material for RM for poultry meat composition preparation -1) white meat (chicken breast); 2) red meat (chicken thigh). The procedure included pounding, boiling, freezing and lyophilisation (syn. freeze drying). The researches for homogeneity were implemented with hot air dryer standard system from the State primary standard GET 173-2017. Measurement of nitrogen (protein) mass fraction was performed on State secondary standard GVET176-1-2010. Measurements of fat mass fraction were performed with accordance to State Primary Reference Measurement Procedure.The total time of lyophilization process for samples № 1 and № 2 was 19 and 28 hours, respectively. The total mass loss for sample № 1 was about 63 %, for sample № 2 was about 65 %. The difference in material moisture mass fraction values of materials dried on different trays of freeze dryer was statistically significant, i. e., material was non-homogeneous. To obtain a homogeneous material, an additional homogenization procedure was performed: grinding in a laboratory mill, sieving through a sieve, thorough mixing and conditioning. The certified values of moisture, nitrogen, protein, fat mass fraction for the sample № 1 were accordingly 4,5 %, 14,74 %, 92,1 %, 7,9 %. The same values in the same sequence were 6,3 %, 12,21 %, 76,3 %, 23,8 %.The procedure of lyophilisation was developed for production of reference materials for composition of boiled and freeze-dried poultry meat. The usage of this lyophilisation system allowed to ensure a RM expiration date of six months at ambient temperature of (7±3) °C and relative humidity no more than 60 %. The Reference Materials for composition of boiled and freeze-dried poultry meat was added into Register of certified RMs under № GSO 11276-2019 by the results.

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PAHs in animal tissues – the analytics of PAHs in new reference materials and their homogeneity

Analytical Methods ◽

10.1039/c6ay01858k ◽

2017 ◽

Vol 9 (1) ◽

pp. 76-83 ◽

Cited By ~ 6

Author(s):

Anna Kiełbasa ◽

Bogusław Buszewski

Keyword(s):

Reference Materials ◽

Animal Tissues ◽

Biological Matrices ◽

Certified Values

Extraction and determination of PAHs in biological matrices of new reference materials, and determination of certified values and homogeneity of these materials are described.

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The Implications of HClO4 for Dissolving Large Masses of Low Level Os in Metal Sulfides and Factors that Influence Re-Os Dating

Applied Sciences ◽

10.3390/app10186218 ◽

2020 ◽

Vol 10 (18) ◽

pp. 6218

Author(s):

Bingyu Gao ◽

Wenjun Li ◽

Lianchang Zhang ◽

Jun Gao

Keyword(s):

Reference Materials ◽

Traditional Method ◽

Isotope Exchange ◽

Heating Temperature ◽

Metal Sulfide ◽

Metal Sulfides ◽

Sample Weight ◽

Aqua Regia ◽

Certified Values ◽

Larger Sample

In general, no more than 1 g of metal sulfide can be completely digested in 20 mL of inverse aqua regia using the Carius tube technique. In this study, the sample weight increased after adding HClO4 to inverse aqua regia while the volume of acid concurrently decreased significantly. Three grams of metal sulfide were digested in 12 mL of acid (3 mL of HClO4 and 9 mL of inverse aqua regia) via the HClO4-inverse aqua regia method. The results using molybdenite reference materials JDC and HLP mixed with 3 g of pyrite were consistent with certified values. Compared to the traditional method, the HClO4-inverse aqua regia method could dissolve a larger sample mass (3 g) with a smaller volume of acids (12 mL). We simultaneously found that the oxidation of digestion acids greatly affected the Os signal but had no influence on the equilibrium of isotope exchange between 185Re and 190Os spikes in Re and Os samples. Remarkably, the heating temperature was the most significant factor influencing the equilibrium of isotope exchange, and the Os in a sample was not equilibrated with the spike until the heating temperature reached 190 °C.

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Updated certified values of the lithium isotopic reference materials IRMM-016, IRMM-015 and IRMM-615

Rapid Communications in Mass Spectrometry ◽

10.1002/rcm.3930 ◽

2009 ◽

Vol 23 (6) ◽

pp. 937-938 ◽

Cited By ~ 2

Author(s):

Steluta Duta ◽

Michael Berglund ◽

Philip Taylor

Keyword(s):

Reference Materials ◽

Certified Values

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Reference materials as crucial tools for quality assurance and control in food analysis

Pure and Applied Chemistry ◽

10.1351/pac200678010135 ◽

2006 ◽

Vol 78 (1) ◽

pp. 135-143 ◽

Cited By ~ 12

Author(s):

Hendrik Emons ◽

Andrea Held ◽

Franz Ulberth

Keyword(s):

Quality Assurance ◽

Reference Materials ◽

Trace Element Analysis ◽

Rice Flour ◽

Analytical Quality ◽

Analytical Quality Assurance ◽

Element Analysis ◽

And Control ◽

Certified Values

The role of reference materials (RMs) in analytical quality assurance (QA) is outlined with special emphasis on trace element analysis of foodstuff. Crucial aspects for the development of such food RMs are illustrated by a recent example of trace elements in rice flour. Major influences on the uncertainty of certified values are discussed and possibilities to enhance the availability and fitness-for-purpose of RMs as well as their proper use are indicated.

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Uncertainty limits for certified values of standard reference materials

Fresenius Journal of Analytical Chemistry ◽

10.1007/bf00322505 ◽

1990 ◽

Vol 338 (4) ◽

pp. 411-413 ◽

Cited By ~ 2

Author(s):

John J. LaBrecque

Keyword(s):

Reference Materials ◽

Standard Reference Materials ◽

Certified Values

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Certification of Matrix Reference Materials in Chemical Measurement: A New Basis for Adopting a Consensus Value Derived from a Proficiency Test

10.26434/chemrxiv.8320610 ◽

2019 ◽

Author(s):

Michael Thompson ◽

Philip Potts ◽

Peter Webb

Keyword(s):

Analytical Chemistry ◽

Proficiency Testing ◽

Reference Materials ◽

Proficiency Test ◽

Chemical Measurement ◽

Proficiency Tests ◽

Consensus Value ◽

Iso Guide 35 ◽

Consensus Values ◽

Certified Values

ISO Guide 35 (2017) specifies conditions for the certification of matrix reference materials via information from proficiency tests. Many scientists involved in the provision of proficiency tests for analytical chemistry have concluded that the Guide 35 conditions are effectively fulfilled by identifying certified values with properly-derived consensus values. However, the claim that such reference materials are ‘certified’ is likely to be challenged by traditional metrologists. This paper proposes to move beyond this unresolved situation to put certification via proficiency testing on an unassailable footing. The proposal therefore is not a questionable fulfilment of the Guide 35 conditions but an unrelated paradigm for certification.

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Development of certified reference materials set for opened porosity of solid substances and materials

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2021-3-58-66 ◽

2021 ◽

pp. 58-66

Author(s):

Egor P. Sobina ◽

Ilya P. Aronov

Keyword(s):

Reference Materials ◽

Open Porosity ◽

Certified Reference Materials ◽

Measurement Techniques ◽

Measuring Instruments ◽

Measurement Results ◽

And Control ◽

Porosity Measurements ◽

Calibration Laboratories ◽

Certified Values

The article deals with data of research for development of certified reference materials set for opened porosity of solid substances and materials (imitators) (OPGP SO UNIIM set) GSO 11116-2018/GSO 11119-2018. The certified values of open porosity are determined using a gas pycnometer. Certified reference materials are intended for certification of measurement techniques and control of the accuracy of open porosity measurement results for petrophysical studies of core. Certified reference materials can be used for calibration, verification of open porosity measurements of rock and for testing of measuring instruments. A complete budget of the CRM uncertainty is presented, taking into account changes in ambient temperature when it used in testing and calibration laboratories.

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Certification of Matrix Reference Materials in Chemical Measurement: A New Basis for Adopting a Consensus Value Derived from a Proficiency Test

10.26434/chemrxiv.8320610.v1 ◽

2019 ◽

Author(s):

Michael Thompson ◽

Philip Potts ◽

Peter Webb

Keyword(s):

Analytical Chemistry ◽

Proficiency Testing ◽

Reference Materials ◽

Proficiency Test ◽

Chemical Measurement ◽

Proficiency Tests ◽

Consensus Value ◽

Iso Guide 35 ◽

Consensus Values ◽

Certified Values

ISO Guide 35 (2017) specifies conditions for the certification of matrix reference materials via information from proficiency tests. Many scientists involved in the provision of proficiency tests for analytical chemistry have concluded that the Guide 35 conditions are effectively fulfilled by identifying certified values with properly-derived consensus values. However, the claim that such reference materials are ‘certified’ is likely to be challenged by traditional metrologists. This paper proposes to move beyond this unresolved situation to put certification via proficiency testing on an unassailable footing. The proposal therefore is not a questionable fulfilment of the Guide 35 conditions but an unrelated paradigm for certification.

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