The Role of Reference Materials and Reference Methods in Chemical Analysis

Uriano, George A.; Gravatt, C. C.; Morrison, George H.

doi:10.1080/10408347708542696

Cited by 42 publications

(26 citation statements)

References 78 publications

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“…Metrology, the science and practice of precise and reliable measurements, generally involves the quantification and certification of a quantity (property) in a divisible or transportable reference material, the constancy and homogeneity of that quantification in that material having been appropriately tested at or near the highest attainable precision. The important role of reference materials in metrology is to check, verify, disseminate, and calibrate measurement procedures and instrumentation [68]. Such reference materials in atomic-weight and isotopic-composition measurements have become very important and are sure to become more and more indispensable in the future.…”

Section: Atomic-weight Scalementioning

confidence: 99%

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Laeter¹,

Böhlke²,

Bièvre³

et al. 2003

Pure and Applied Chemistry

915

554

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Republication or reproduction of this report or its storage and/or dissemination by electronic means is permitted without the need for formal IUPAC permission on condition that an acknowledgmentAbstract: A consistent set of internationally accepted atomic weights has long been an essential aim of the scientific community because of the relevance of these values to science and technology, as well as to trade and commerce subject to ethical, legal, and international standards. The standard atomic weights of the elements are regularly evaluated, recommended, and published in updated tables by the Commission on Atomic Weights and Isotopic Abundances (CAWIA) of the International Union of Pure and Applied Chemistry (IUPAC). These values are invariably associated with carefully evaluated uncertainties. Atomic weights were originally determined by mass ratio measurements coupled with an understanding of chemical stoichiometry, but are now based almost exclusively on knowledge of the isotopic composition (derived from isotope-abundance ratio measurements) and the atomic masses of the isotopes of the elements. Atomic weights and atomic masses are now scaled to a numerical value of exactly 12 for the mass of the carbon isotope of mass number 12. Technological advances in mass spectrometry and nuclear-reaction energies have enabled atomic masses to be determined with a relative uncertainty of better than 1 × 10 -7 . Isotope abundances for an increasing number of elements can be measured to better than 1 × 10 -3 . The excellent precision of such measurements led to the discovery that many elements, in different specimens, display significant variations in their isotope-abundance ratios, caused by a variety of natural and industrial physicochemical processes. While such variations increasingly place a constraint on the uncertainties with which some standard atomic weights can be stated, they provide numerous opportunities for investigating a range of important phenomena in physical, chemical, cosmological, biological, and industrial processes. This review reflects the current and increasing interest of science in the measured differences between source-specific and even sample-specific atomic weights. These relative comparisons can often be made with a smaller uncertainty than is achieved in the best calibrated "absolute" (= SI-traceable) atomic-weight determinations. Accurate determinations of the atomic weights of certain elements also influence the values of fundamental constants such as the Avogadro, Faraday, and universal gas constants. This review is in two parts: the first summarizes the development of the science of atomic-weight determinations during the 20 th century; the second summarizes the changes and variations that have been recognized in the values and uncertainties of atomic weights, on an element-by-element basis, in the latter part of the 20 th century.J. R. de LAETER et al.

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Section: Atomic-weight Scalementioning

confidence: 99%

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Laeter¹,

Böhlke²,

Bièvre³

et al. 2003

Pure and Applied Chemistry

915

554

View full text Add to dashboard Cite

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“…(1)(2)(3)(4)]. In spite of ambitious standardization projects by authoritative organizations such as the International Federation for Clinical Chemistry and Laboratory Medicine and the US Centers for Disease Control and Prevention (5)(6)(7)(8), there are enough reasons to state that even at the beginning of the 21st century standardization has not been realized (9,10 ).…”

mentioning

confidence: 99%

Feasibility Study of the Use of Frozen Human Sera in Split-Sample Comparison of Immunoassays with Candidate Reference Measurement Procedures for Total Thyroxine and Total Triiodothyronine Measurements

et al. 2005

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Background: Diagnostic manufacturers must ensure/ document metrologically traceable assays. We report on a feasibility study of a split-sample comparison for that purpose. Processed, frozen single-donation sera, assigned target values by candidate reference measurement procedures (cRMPs), were used with immunoassays for total thyroxine (TT 4 ) and triiodothyronine (TT 3 ) as models. Methods: Two serum panels were quantified for TT 4 and TT 3 with validated cRMPs and measured in parallel with at least 14 immunoassays. The results were interpreted in terms of traceability of calibration (trueness) and of the individual measurement result (accuracy) by linear regression analysis and graphical representation against specifications. The commutability of the sera was investigated by parallel analysis of TT 4 in freshly collected but nonfiltered specimens. Results: The TT 4 (TT 3 ) concentrations in the sera (according to the cRMPs) were 64 -269 nmol/L (0.88 -13.7 nmol/L). The method comparison showed that for TT 4 , on average, the immunoassays produced results in agreement with the cRMPs, whereas for TT 3 , results were typically higher. It also demonstrated a consider-

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“…A systematic discussion of the reference methods available today would go beyond the scope of this review (see for example the review given by Uriano & Gravatt (32)) and for this reason (90) that the principle of isotope dilution combined with mass spectrometry (ID-MS) has proved to be particularly suitable above all for the determination of organic substances. Recent reviews on this subject were given by de Leenheer et al (33) and Siekmann (34).…”

Section: Analytical Principles For Reference Methodsmentioning

confidence: 99%

Reference Methods as a Basis for Accurate Measuring Systems

Büttner

1991

Clinical Chemistry and Laboratory Medicine

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Summary:Reference methods, äs part of a reference System, are essential for improving the accuracy of routine methods. They can help to establish worldwide compatibility of clinical chemical measurements and they provide an objective basis for quality control measures. The subject of analytical errors is treated in detail, then the concept of reference methods is developed. This review emphasizes the fundamental metrological aspects of reference methods and reference measurement technology. An overview is given of the most important analytical principles used for reference methods in clinical chemistry. The particular problems of reference methods for the determination of the catalytic activity concentration of enzymes are outside the scope of this review.

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The Role of Reference Materials and Reference Methods in Chemical Analysis

Cited by 42 publications

References 78 publications

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Atomic weights of the elements. Review 2000 (IUPAC Technical Report)

Feasibility Study of the Use of Frozen Human Sera in Split-Sample Comparison of Immunoassays with Candidate Reference Measurement Procedures for Total Thyroxine and Total Triiodothyronine Measurements

Reference Methods as a Basis for Accurate Measuring Systems

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