The external review committee on pure reference materials at the National Analytical Reference Laboratory

The preceding paper described the implementation of a quality assurance system suitable for accreditation to ISO Guide 34 by the Pure Substance Reference Material (PSRM) team of the National Analytical Reference Laboratory (NARL). One of the key components of this system has been the establishment of an external advisory committee that scrutinises each candidate material that is to be offered as a reference material. At the time of writing 190 reference materials were available from NARL, including a range of illicit drugs and agricultural chemicals in addition to anabolic steroids and their metabolites, and all have been reviewed by the external committee prior to final approval by the accredited production signatory.     

The work of ISO-REMCO’s accreditation task group

This paper discusses some of the work of ISO-REMCO’s Task Group 4 (TG4) – the Accreditation TG, giving firstly a brief account of the recently published ISO Guide 34 – which gives guidance on the type of quality system a reference material producer should have in place. Secondly, work on the future development of Guide 34 to produce a document against which it will be possible for producers to be accredited without reference to ISO Guide 25 is discussed, and thirdly, the possible formation of an international register of CRM producers, which will provide users with information about the quality status of different producers, is considered.     

Accreditation of reference material producers: an Australian perspective

The National Association of Testing Authorities, Australia has operated an accreditation program for reference material producers since 1997 with accreditation now being offered to ISO Guide 34 (2000). This paper discusses the benefits and disadvantages to both the producers and the users of reference materials (testing laboratories) and their clients of a formal system of third-party accreditation of reference material producers. The merits of using ISO Guide 34 (2000) rather than ISO/IEC 17025 as the core standard in the accreditation process are discussed.     

Accreditation of reference material producers: Let's get it right!

The accreditation of testing and calibration laboratories to ISO/IEC 17025 is increasingly calling for the accreditation of reference material (RM) producers. Two international guides, ISO Guide 34 (2000) " General requirements for the competence of reference material producers" issued by the ISO Committee on Reference Materials and ILAC-G 12 " Guidelines for the requirements for the competence of reference material producers" issued by the International Laboratory Accreditation Cooperation (ILAC), are already in use for this purpose. Recently however initiatives have been launched to accredit RM producers to ISO 17025 as calibration laboratories and it has been suggested that a combination of ISO/IEC 17025 " General requirements for the competence of testing and calibration laboratories" and ISO Guide 34 may be the best option. This publication is an expression of the position of the ISO Committee on Reference Materials (ISO/REMCO) on the standards and guides currently in use in the accreditation of RM producers. The paper discusses the advantages and disadvantages of these standards and guides from the perspective of benefit to RM producers and RM users. In conclusion, the use of ISO Guide 34 alone or in combination with ILAC-G 12 is the preferred system for the accreditation of RM producers. Therefore ISO/REMCO strongly encourages all accreditation bodies to adopt ISO Guide 34.     

Implementing the GUM in the certification of reference materials: the revision of ISO Guide 35

The availability of certified reference materials, certified in accordance to the GUM is an important tool for the proper estimation of measurement uncertainty in routine analysis. Many CRMs may suffer from incomplete or wrongly estimated uncertainties, mainly due to lack of guidance on how to implement the GUM in the production of CRMs. In particular the inclusion of the impact of inhomogeneity and instability in the uncertainty budget is often missing. The ongoing revision of ISO Guide 35 aims to fill this gap in providing guidance how (batch) inhomogeneity and instability can be translated into measurement uncertainty. The structure of the current ISO Guide 35 has been maintained as far as possible, but major parts underwent revision to become better aligned with GUM and ISO Guide 34 (2000). Received: 9 April 2001 Accepted: 22 October 2001     

Experiences from the assessment of proficiency testing providers

Following a pilot project in 2001–2002, UKAS accredited nine PT providers. During the course of the pilot and at subsequent surveillance visits, UKAS has gained experience in assessing organisations against the criteria detailed within ISO/IEC Guide 43-1:1997 and ILAC G13:2000. This article explores some of the key aspects that arose during the pilot and how UKAS has accommodated the addition of the accreditation of PT providers in to its range of services.Presented at the Eurachem PT Workshop September 2005, Portorož, Slovenia     

Reference materials in the Russian system of accreditation of analytical laboratories

 This article is devoted to the role of reference materials (RMs) in chemical analysis and their main applications in analytical laboratories. The principal requirements of the RMs used in accredited laboratories in the Russian Analytical Laboratories Accreditation System (SAAL) are presented. These include the basic regulatory and metrological requirements of RMs. Finally, a review of the provision of RMs used for the analytical control of various test objects is presented. Received: 9 August 1998 / Accepted: 9 November 1998     

Accreditation of reference material producers

 The use of reference materials is the most pragmatic means by which the analyst can achieve comparability of data. Reference material producers therefore need to have adequate quality systems in place for ensuring the reliability of their materials. In order to provide guidance to both producers and assessors, ISO Guide 34 has recently been produced detailing the quality system requirements for the production of reference materials. CITAC, REMCO and ILAC are now collaborating in the revision of this guide to produce a free-standing document detailing the general requirements for the competence of reference material producers. This paper discusses some of the more important issues described in these documents. The possible formation of an international register containing details of a reference material producer's quality system status is also discussed.     

Outline for the revision of ISO Guide 35

The production of reference materials (RMs) is a key activity for the improvement and maintenance of a worldwide coherent measurement system. As detailed in ISO Guide 33, RMs with different characteristics are used in measurements, such as calibration, quality control and method validation, as well as for the assignment of values to other materials. Currently, ISO Guide 35 is in its third edition after it was revised in 2006. The Guide was developed to support best practices in the value assignment to specified properties of Certified Reference Materials (CRMs). This Guide gives general guidance and explains concepts to assist the understanding and development of valid methods to assign values to the properties of a reference material, including the evaluation of their associated measurement uncertainties, and the establishment of their metrological traceability. From the outcome of a systematic review of ISO Guide 35 among the members of ISO/REMCO, the ISO Committee on Reference Materials, it followed that there is a need for revising the current edition of ISO Guide 35. The mandate for the revision is focused on editorial updates to explain the concepts in more detail. It is not envisaged that major technical changes will be introduced. This paper explains the approach and rationale for the revision of ISO Guide 35 and invites comments from the users of the current edition of ISO Guide 35.     

Metrological compatibility—a key issue in future accreditation

Global acceptance of measurement results from accredited laboratories is linked to their metrological compatibility, defined in VIM 3 as a comparison between all measurement results in a set. It is therefore most unfortunate that a recent IUPAC/CITAC Guide applies the same term to a comparison between a certified value and the measured quantity values in a set.     

Certification of herbal products: an urgent need for appropriate methods

 Analytical chemists should focus their attention on establishing validated analytical methods for herbal pharmaceutical formulations. Efforts should also be made to have the reference materials for herbal products both accessible and commercially available. Received: 25 January 2000 / Accepted: 2 March 2000     

Development and supply system of reference materials based on the Measurement Law in Japan

 Analytical instruments used for measurements of air and water pollution are calibrated by using reference materials such as standard gases and standard solutions. In Japan, since the middle of the 1970s, those reference materials which are traceable to the national standards maintained at national research institutes have been supplied to users by reference material producers. In order to establish the primary standards and to secure the traceability from the working standards to the national ones, various analytical methods such as coulometric, titrimetric and gravimetric analyses for purity determination and highly sensitive atomic spectrometry for trace analysis have been developed as the primary methods and reference methods. The Japanese Measurement Law, revised in 1992, has introduced a new traceability system in which a public organization, a "designated calibration body", can also prepare and maintain the national standards under the advice and instruction of national research institutes. The designated calibration body can provide calibration services to reference material producers (accredited calibration bodies) by using the national standards. The reference materials supplied in conformity with the traceability system include standard gases, pH standard solutions, metal standard solutions and non-metal ion standard solutions. Received: 4 October 1996 Accepted: 2 December 1996     

Accreditation system for reference material producers and certified reference materials for iron and steel in Japan

  ISO 9000 series strictly requires traceability to national or international measurement standards. It is becoming more necessary to make clear the concept of traceability of measurement standards with respect to chemical composition and to accredit the reference material producers. In Japan, the accreditation system for reference material producers is considered to satisfy the requirement of ISO Guide 34, ISO 9000 series and ISO/IEC Guide 25, while the producer fulfills the concept of traceability of measurement standards. This paper describes the production of iron and steel reference materials in Japan relating to the international standardization of methods (written standards) and accreditation of reference material producers. Received: 11 October 1996 Accepted: 5 December 1996     

Contribution to the certification of cadmium and lead amount content in the BCR CRM-278R mussel tissue by isotope dilution mass spectrometry

 Metrological certification through a primary method of measurement and how it can be achieved is demonstrated in this paper, using the example of re-certification of cadmium and lead content in a biological material, the Bureau Communataire de Reference, reference material CRM-278R mussel tissue. The measurement method used was isotope dilution in combination with inductively coupled plasma mass spectrometry. Microwave digestion was applied to the samples prior to the measurements. A detailed uncertainty budget was evaluated according to the International Organisation of Standardisation, Guide to the Expression of Uncertainty and EURACHEM Guide, resulting in an expanded uncertainty. Received: 20 August 1999 / Accepted: 3 January 2000     

Accreditation of pathology laboratories in Finland

 The Finnish Accreditation Service (FINAS) accredits testing laboratories in all fields including medical laboratories according to European standard EN 45001 and ISO Guide 25. At the beginning of 1998, FINAS published a recommendation on how to apply general standards in histo- and cytopathology. Four pathology laboratories have been accredited to date. FINAS has not included autopsies in these accreditations. The International Academy of Pathology (IAP)-Finnish Division has recognized 21 pathology laboratories according to standards of their own. Although accreditation by FINAS is not connected to the system of the IAP-Finnish Division, the requirements are very similar in both. Less than half of the pathology laboratories in Finland participate in national quality improvement programme or have been accredited by FINAS.     

Reference materials – a view from a small country

ISO/IEC 17025 has an increased emphasis on traceability and estimation of uncertainty of measurement compared with ISO Guide 25. Demonstration of traceability is a new concept in analytical chemistry and depends on access to relevant reference materials or use of reference methods. Until now most reference materials used in New Zealand have been imported, because they offered international comparability. New Zealand is currently starting to develop the required infrastructure so that it will be able to produce unique reference materials that will contribute to the total international effort in improving the reliability of analytical chemistry. Received: 12 October 2000 / Revised: 18 January 2001 / Accepted: 23 January 2001     

Estimating the uncertainty of stability for matrix CRMs

The new version of ISO Guide 34 requires producers of certified reference materials (CRMs) to include contributions of possible instability to the overall CRM uncertainty, to obtain a value for the uncertainty in compliance with the Guide to the Expression of the Uncertainty in Measurement (GUM). A pragmatic approach to estimating the uncertainty of stability is presented. It relies on regression analysis of stability data with subsequent testing of the slope of the regression line for significance. If the slope is found to be statistically insignificant, a shelf life is chosen and the uncertainty connected with this time is estimated via the standard deviation of the slope. This uncertainty is included in the overall uncertainty of the CRM. This approach is explained with examples showing its applicability to matrix CRMs. Received: 12 October 2000 / Revised: 2 January 2001 / Accepted: 3 January 2001     

Systematic comparison of post-column isotope dilution using LC-CO-IRMS with qNMR for amino acid purity determination

Analytical and Bioanalytical Chemistry - Determination of the purity of a substance traceable to the International System of Units (SI) is important for the production of reference materials...     

Metrology for chemical engineers

 The first full-semester course on Quality Assurance in Chemical Measurement was held at the Technical University of Denmark from September to December 1999. The course required sufficient knowledge of basic statistics to understand and apply the methods recommended in ISO 5725–1/6 Accuracy of Measurement Methods and Results. The main purpose of the course was, however, to familiarize PhD students with the BIPM philosophy, using the International Organization for Standardization (ISO) Guide to Expression of Uncertainty in Measurement, which was accepted by IUPAC and other international scientific organizations in 1993. Chemists are notoriously reluctant to accept the BIPM philosophy, but the appearance of a new Draft Guide Quantifying Uncertainty in Analytical Measurement at the EURACHEM Workshop in Helsinki in June 1999 stimulated us to make an attempt to overcome such chemical prejudice. After thorough reading of the examples presented in the Draft Guide, each of the participating students had to prepare an uncertainty budget for their own particular project and present it to the other participants for discussion. Eventually the students learned how to verify their uncertainty budgets by means of experimental results; this invariably entailed a re-evaluation of the uncertainty components in the original budget. The revised budget was again verified, and this iteration was continued until the budget correctly predicted the uncertainty of individual results covering the whole range of applicability of the analytical method. The paper presents the detailed structure of this first course, as well as improvements in the next course scheduled for the year 2000.