Metrology in chemistry – a rocky road

Kipphardt, Heinrich; Matschat, Ralf; Panne, Ulrich

doi:10.1007/s00604-007-0909-6

Cited by 8 publications

(4 citation statements)

References 16 publications

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“…The necessity to establish primary standards for all of the relevant types of chemical analytes has the consequence of requiring an extremely large effort for each NMI, as laid out in [8]. Additionally, matrix effects make the practical implementation of metrology in chemistry more difficult.…”

Section: Introductionmentioning

confidence: 99%

On the way to SI traceable primary transfer standards for amount of substance measurements in inorganic chemical analysis

et al. 2023

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During its 25 years of existence, the Inorganic Analysis Working Group of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM IAWG) has achieved much in establishing comparability of measurement results. Impressive work has been done on comparison exercises related to real-world problems in fields such as ecology, food, or health. In more recent attempts, measurements and comparisons were focused on calibration solutions which are the basis of most inorganic chemical measurements. This contribution deals with the question of how to achieve full and transparent SI traceability for the values carried by such solutions. Within this framework, the use of classical primary methods (CPMs) is compared to the use of a primary difference method (PDM). PDM is a method with a dual character, namely a metrological method with a primary character, based on the bundling of many measurement methods for individual impurities, which lead to materials with certified content of the main component. As in classical methods, where small corrections for interferences are accepted, in PDM, many small corrections are bundled. In contrast to classical methods, the PDM is universally applicable to all elements in principle. Both approaches can be used to certify the purity (expressed as mass fraction of the main element) of a high-purity material. This is where the metrological need of National Metrology Institutes (NMIs) for analytical methods meet the challenges of analytical methods. In terms of methods, glow discharge mass spectrometry (GMDS) with sufficient uncertainties for sufficiently small impurity contents is particularly noteworthy for the certification of primary transfer standards (PTS), and isotope dilution mass spectrometry (IDMS), which particularly benefits from PTS (back-spikes) with small uncertainties, is particularly noteworthy for the application. The corresponding relative uncertainty which can be achieved using the PDM is very low (< 10−4). Acting as PTS, they represent the link between the material aspect of the primary calibration solutions and the immaterial world of the International System of Units (SI). The underlying concepts are discussed, the current status of implementation is summarised, and a roadmap of the necessary future activities in inorganic analytical chemistry is sketched. It has to be noted that smaller measurement uncertainties of the purity of high-purity materials not only have a positive effect on chemical measurements, but also trigger new developments and findings in other disciplines such as thermometry or materials science. Graphical Abstract Primary Transfer Standards (PTSs) are the link between the immaterial world of the International System of Units (SI) and the material aspects of the primary calibration solutions.

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Section: Introductionmentioning

confidence: 99%

On the way to SI traceable primary transfer standards for amount of substance measurements in inorganic chemical analysis

et al. 2023

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“…Traceability to the SI means that the results are metrologically linked to a measurement unit of the SI [2], typically the unit mole or kilogram in case of chemical and biological measurement results, via a so-called traceability chain (see figure 1, adopted from [3]). Even though today the concept of traceability is widely accepted, in the early days, most analytical chemists were unconvinced of the value of issues such as traceability and measurement uncertainty [4,5]. To establish SI-traceability, in inorganic chemistry, usually a fully characterized solid material with an assigned purity such as a high purity metal or salt serves as the primary realization of the SI unit for amount of substance of the respective element.…”

Section: Introductionmentioning

confidence: 99%

SI-traceable monoelemental solutions on the highest level of accuracy: 25 years from the foundation of CCQM to recent advances in the development of measurement methods*

et al. 2019

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Within the Working Group on Inorganic Analysis (IAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) international key comparisons and pilot studies related to inorganic analysis are carried to ensure consistency in this field at the highest level. Some of these comparisons deal directly with the preparation and characterization of monoelemental solutions or with topics, closely related. The importance of monoelemental solutions lies in the fact that almost every measurement in inorganic analysis relies on the comparison with either a reference material, or references in form of solutions, usually (mono)elemental solutions. All quantitative measurement approaches, e.g. isotope dilution or standard addition, need an accurate reference solution made from a well characterized reference material, prepared under full gravimetric control. These primary (monoelemental) solutions do not only serve as arbitrary references/calibration solutions, but they also link up measurement results to the International System of units (SI), this way establishing the so-called metrological traceability to a measurement unit of the SI. Without such solutions on the highest possible level of accuracy and with the smallest possible associated uncertainties (for e.g. element content and/or impurities), an analysis itself can never be as good as it could be with appropriate reference solutions. This article highlights select key comparisons and pilot studies dealing with monoelemental solution-related topics within the IAWG from the foundation of CCQM—25 years ago—up to latest achievements in the field of inorganic analysis.

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“…In this situation, accurate and reliable relative analysis methods should be applied, which are based on different principles, such as quantitative nuclear magnetic resonance (qNMR), differential scanning calorimetry (DSC), mass balance method etc. .…”

Section: Introductionmentioning

confidence: 99%

Certification of a New Naringenin Reference Material by Coulometric Titrimetry Combined HPLC‐MS

Yang

Zhang

et al. 2016

Electroanalysis

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Certified reference material (CRM) is a kind of measuring tool with high accuracy and traceability. CRMs are the important guarantee of accurate and reliable results of analysis methods. They are the medium of international communication of experimental data. CRMs are widely used in various fields and play a pivotal role in analytical science. However, in the characterization of CRMs, available absolute analysis methods are very limited. In this situation, accurate and reliable relative analysis methods should be applied. In this work, coulometric titrimetry (CT) was applied to the characterization of flavone naringenin CRM according to its structure. For further illustration of the principle of CT, high‐performance liquid chromatography tandem mass spectrometry (HPLC‐MS) was utilized to analyze the titration products in detail. As the conclusion of this paper, the advantages and the influence factors of CT were given. Mass balance (MB) method was employed to verify the result of CT, and consistent result was obtained.

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Metrology in chemistry – a rocky road

Cited by 8 publications

References 16 publications

On the way to SI traceable primary transfer standards for amount of substance measurements in inorganic chemical analysis

On the way to SI traceable primary transfer standards for amount of substance measurements in inorganic chemical analysis

SI-traceable monoelemental solutions on the highest level of accuracy: 25 years from the foundation of CCQM to recent advances in the development of measurement methods*

Certification of a New Naringenin Reference Material by Coulometric Titrimetry Combined HPLC‐MS

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