Stability Of Reference Materials Research Articles

Creation of reference materials of specific electrical conductivity of aviation fuels as a component of ensuring the uniformity of measurements at chemmotology laboratories

Today in Ukraine there are no reference materials of aviation fuels, including very important reference materials of specific conductivity of aviation fuels. This makes impossible to ensure the accredited laboratories activities for testing aviation fuels. The relevance of creating a set of reference materials of specific electrical conductivity of aviation fuels is caused by the need to ensure the uniformity, traceability and reliability of measurements when assessing the suitability of measurement (testing) methods and proficiency testing in testing chemmotology laboratories accredited for compliance with international standard ISO/IEC 17025. It is also caused by the intermediate inspections of measuring equipment and intra-laboratory quality control over the entire range of measurement methods realizations. An important characteristic for the safety of aircraft engines is the specific conductivity of fuels. This characteristic can be quite easily and accurately measured in each unit from the batch of reference materials. A wide range of values of specific conductivity of reference materials can be obtained with the help of specialized additives. In the article the authors analyze the existing regulations and publications on procedures for the manufacture and use of fuel reference materials in general and specific requirements for fuels used in aviation. The issue of manufacturing is considered and the results of experimental researches of homogeneity and stability of reference materials of aviation fuel taking into account the requirements of DSTU-N ISO Guide 35:2018 are given. It is proposed to create a number of aviation fuel reference materials with antistatic additive and different levels of the certified characteristic value at the range from 25 pS/m to 650 pS/m.

Report on the 36th meeting of ISO/REMCO

The meeting report of the 39th annual ISO/REMCO meeting gives an update on the current activities of the ISO Committee for Reference Materials. The key topics that were discussed at this year’s meeting included ways of increasing the active membership of the committee and the interactions of the committee with its organizations in liaison. New opportunities to promote the deliverables of the committee and its other activities were also explored. ISO Central Secretariat approved a project for ISO/REMCO to develop a new website that could be used for more effective information sharing. The progress that was made with the work programme of the committee is also discussed in the report. This includes the completion of the project to convert ISO Guide 34 into a harmonized international standard ISO 17034. Progress was also made with the drafting of a new edition of ISO Guide 35 which provides guidance for the characterization and the assessment of the homogeneity and stability of reference materials. The committee is also exploring the possibility of developing some more sector-specific guidance for reference material producers in emerging fields, such as biological measurements.

WHO technical workshop on stability of reference materials for biological medicines and in vitro diagnostics, Geneva, Switzerland, 28–29 November 2005

In November 2005, the World Health Organization convened an informal technical workshop on the stability of reference materials for biological medicines and in vitro diagnostics. The meeting was attended by experts from WHO collaborating centres in the area of biological standardization, national control laboratories, industries and other relevant organizations. The consultation group discussed current practices and approaches to predicting and monitoring the stability of biological reference materials. The group agreed to the need for establishing a working group (i) to continue dialogue on potential issues encompassing the principles, strategies and practicality for assuring the stability of WHO international reference standards for biological medicines and in vitro diagnostics and (ii) to develop more detailed guidance for assessment of the stability of WHO international biological reference materials.

Homogeneity and stability of reference materials

Homogeneity and stability are two crucial characteristics of any certified reference material (CRM). Utmost care must be taken during preparation to create materials as homogeneous and stable as possible. Degradation can generally be minimised by reducing the water activity of the material to a level between 0.15 and 0.35. However, careful preparation by itself is not enough. Positive demonstration of homogeneity and stability is required from the perspective of implementing uncertainty calculus according to the Guide to the Expression of Uncertainty in Measurement (GUM). In many cases, homogeneity and stability studies fail to give sufficient quantitative information on homogeneity and stability, mainly because of a lack of measurement repeatability and insufficient number of replicates. In this work, some solutions to these problems and their implications are presented.

The preparation of animal samples incurred with residues: CRMs for veterinary drugs and the BCR programme

The BCR Programme of the Commission of the European Communities has undertaken an extensive series of projects designed to support the implementation of Community policy concerning the use of veterinary drugs in farm animals and the monitoring of their residues. This paper summarizes the materials under preparation and the general approach to preparation and the testing of homogeneity and stability of reference materials.

Stability of reference materials

The problem of stability of reference materials is particularly difficult when dealing with complex biological matrices and certification of the content of relatively unstable organic components. This paper considers two aspects of the problem: a) the preparation and packaging of material in a form which gives the greatest likelihood of achieving acceptable stability; b) the design of the measurement studies undertaken to monitor short-term stability for shipment, laboratory handling and long-term storage stability.