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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.8, #7-8)
Accreditation in Global Trade—ILAC and IAF Joint Conference on 23–24 September 2002, Berlin, Germany
by Hans Ulrich Mittmann; Manfred Golze; Anita Schmidt (pp. 315-316).
Availability of reference materials: COMAR the database for certified reference materials by Rita Pradel; Thomas Steiger; Harry Klich (pp. 317-318).
COMAR is the international database for certified reference materials. A new user-friendly web-based version, COMAR2, has been developed by BAM and CONET Consulting AG which will be available in December 2002. The advantages of COMAR2 are briefly explained.
Keywords: COMAR; International database; Certified reference material (CRM)
Traceability issues in measurement by Andrew Wallard (pp. 319-322).
This paper reviews the current state of play of the Mutual Recognition Arrangement created by the International Committee for Weights and Measures in 1999. The aim of the MRA is to provide a framework within which National Metrology Institutes can demonstrate the equivalence of their realisations of the units and quantities of the SI system to which accredited laboratories are traceable. The article offers some views on the need for traceable measurements, their relevance to technical barriers to trade, and the use that is being made of the MRA framework by national and international bodies.
Keywords: Traceability; Mutual recognition; CIPM
Quality assurance program for the chemical characterization of soils by Maria A. Trancoso; Margarida M. Correia dos Santos; Maria L. Simões Gonçalves (pp. 323-333).
A quality assurance program has been developed both to assess and to demonstrate the quality of the results produced by an analytical diagram applied to the chemical characterization of soils. The composition of several soils was determined following procedures based on the methods that are applied to silicate materials. A combination of acid decomposition followed by fusion allows the determination of SiO2, Al, Fe, Ca, Mg, Ti, P, Mn, Cd, Co, Cr, Cu, Ni, Pb and Zn; a specific acid attack was used for Hg analysis and an acid mixture decomposition to analyse Na, K, Li and Sr. Several quality control parameters, namely calibration function characteristics, limits of detection, limits of quantification, quality control standards, duplicate analysis, spike recoveries and certified reference materials analysis, are introduced, evaluated and discussed. The results obtained for the certified reference materials show that the analytical diagram gave acceptable accurate values for the elements applying the quality assurance program proposed.
Keywords: Quality assurance; Method validation; Chemical characterization of soils; Precision; Accuracy; Spike recoveries
Measurement uncertainty and doping control in sport by Adriaan M. H. van der Veen (pp. 334-339).
In a series of alleged cases of doping in sport, the assessment of (non-) compliance with an established threshold value has been under debate. From several cases witnessed, it has been concluded that the work of some of the laboratories responsible for doping control does not comply with present quality requirements, most notably those of ISO/IEC 17025. In all cases studied, the observed value is just above the threshold, and a credible statement of measurement uncertainty is lacking. National accreditation bodies should pay specific attention to the latter issue, as the uncertainty statement is part of the material evidence of a (alleged) doping offence, and, as such, an important integral part of the accreditation status of a laboratory and its scope. The fight against doping is based on proper concepts and principles, but it has been noted that in some cases practice does not always follow the requirements set by the system.
Keywords: Doping control; IOC; Measurement uncertainty; Accreditation; Compliance testing
Traceability in laboratory medicine by Mathias M. Müller (pp. 340-345).
In laboratory medicine meaningful measurements are essential for diagnosis, risk assessment, treatment and monitoring of patients. Thus methods applied in diagnostic measurements must be accurate, precise, specific and comparable among laboratories. Inadequate or incorrect analytical performance has consequences for the patients, the clinicians, and the health care system. One key element of metrology is the traceability of a measurement result to the SI system ensuring comparable results. This principle is described in the ISO/TC 212/WG2 N65 prEN 17511 Standard. In addition to the principles of metrology, the clinical usefulness, the diagnostic needs, and the biological and disease associated variations in patients' specimens have to be considered when the analytical biases for diagnostic purposes are defined. It must be the general goal of diagnostic laboratories to produce results that are true and comparable worldwide. The recent European in vitro diagnostic (IVD) Directive 98/79 EC follows the above mentioned standard of the International Organization for Standardization (ISO) and the European Committee for Standardization (CEN) requesting its application for all IVD reagents used within the European Union. This new European legislation will have a worldwide impact on manufacturers and clinical laboratories and will be implemented in 2003. It states that "traceability of values assigned to calibrators and/or control materials must be assured through available reference measurement procedures and/or available reference materials of a higher order". Thus a worldwide reference system needs to be established by collaboration and mutual recognition between the United States National Institute of Standards and Technology (NIST), European Metrology Institutes (EUROMET), regulatory bodies (e.g. United States Food and Drug Administration, FDA) the IVD industry and professional organizations (e.g. International Federation of Clinical Chemistry and Laboratory Medicine, IFCC). In June 2002, in Paris, representatives of international and regional organizations and institutions decided to form the "Joint Committee on Traceability for Laboratory Medicine" (JCTLM), which will support industry in registration and licensing of the "CE" label to test systems conforming to the IVD Directive.
Keywords: Traceability; Laboratory medicine; Biological variation; Analytical bias; Quality assurance; Standardization; Reference measurement system; Joint Committee on Traceability for Laboratory Medicine
Primary methods for the measurement of electrolytic conductivity by Freek Brinkmann; Niels Ebbe Dam; Eva Deák; Francesca Durbiano; Enzo Ferrara; Judit Fűkő; Hans D. Jensen; Michal Máriássy; Rubina H. Shreiner; Petra Spitzer; Uwe Sudmeier; Michael Surdu; Leoš Vyskočil (pp. 346-353).
This paper surveys the state of the art for primary methods for the evaluation of electrolytic conductivity in aqueous solutions as they are currently carried out in several national metrological institutes (NMIs). The theoretical and practical basic knowledge of this measurement is described. Analysis of and comments on the different approaches are offered to give emphasis to technical difficulties and possible solutions. Further development is foreseeable, ensuring a common effort for the sharing of expertise that has been undertaken at the NMIs. In particular, improvements are expected towards traceable measurements of solutions with conductivity values lower than those actually standardized, down to the level of ultrapure water.
Keywords: Electrolytic conductivity; Metrology in chemistry; Primary methods
Measurement uncertainty—Surveys about customers' knowledge, reactions and needs by Ulf Örnemark; Magnus Holmgren (pp. 354-358).
During discussions early in 2000, representatives of accredited analytical laboratories expressed concern about what the customers' reactions might be when the new requirements for evaluating and reporting uncertainty are implemented. In collaboration with accreditation bodies, authorities, laboratories and interest organisations, a two-page leaflet was produced. It was intended to be used by testing laboratories as information, e.g. together with the test report. To gain further insight into customers' views on measurement uncertainty, two surveys were conducted among some 1,200 Swedish customers. The result shows that the majority of them need and value uncertainty statements in the test report.
Keywords: Measurement uncertainty; SME; Testing; Chemical analysis; Education and training
Uncertainty assessment of environmental tritium measurements in water by Manfred Gröning; Kazimierz Rozanski (pp. 359-366).
The method most widely used nowadays to measure environmental tritium levels in water is electrolytic enrichment followed by liquid scintillation spectrometry. Although these techniques have been in use for many years, there is a gap in systematic analysis of the sources of uncertainty associated with this particular application. The paper presents a comprehensive assessment of the individual uncertainty components of the entire analytical process, starting from sample preparation to radioactivity measurement. Examples of the complete uncertainty budget for typical tritium levels in the analysed water samples are included. The relative importance of individual uncertainty components is given and possible ways of improving the overall quality of analyses are discussed.
Keywords: Tritium; Uncertainty assessment; Enrichment; Scintillation spectrometry
Certification is important—modeling and measurement are more important
by Jan Krouwer (pp. 368-368).
TrainMiC: an information platform as a tool for the education of metrology in chemistry by Philip Taylor; Ewa Bulska; Emilia Vassileva; Nineta Majcen; Miloslav Suchanek (pp. 369-371).
One of the initiatives of the Institute for Reference Materials and Measurements of the Joint Research Center of the European Commission in the framework of the support programme for candidate countries is to establish training in metrology in chemistry (TrainMiC). The aim as well as the content of this education programme is presented in this paper. TrainMiC consists of seven modules and a description of each module is given. The main intention of TrainMiC is to disseminate knowledge and awareness on the use of metrological principles in chemical measurements.
Keywords: Metrology in chemistry; Education; TrainMiC
ISTA quality assurance programme – The proficiency test rating system by Martina Rösch (pp. 372-374).
A rating system for determining a laboratory's performance in the International Seed Testing Association (ISTA) Proficiency Test Programme was developed. The proficiency test programme is run 3 times a year with germination testing, purity testing and other seed determination as major test methods. Each test method is given an A, B, C or below minimum performance (BMP) rating for each test round. A calculation of Z-scores is applied for germination and purity testing ,and the in-round rating is determined based on the number of out-of-tolerance results (±2.0) and the sum of absolute Z-scores. In-round rating for determination of other seeds is based on the percentage of retrieved seeds. The in-round rating is accumulated over six test rounds to determine the laboratory's overall testing performance. Laboratories showing a poor overall performance are suspended from accreditation until proof can be given that performance has improved.
Keywords: Proficiency testing; External quality assurance; Accreditation; Seed testing
The GUM and its planned supplemental guides by Maurice Cox; Peter Harris (pp. 375-379).
The work of the Joint Committee for Guides in Metrology on the expression of uncertainty in measurement is considered. Statements are made about the current edition of the Guide to the Expression of Uncertainty in Measurement (the "GUM") and the nature of the process of "GUM revision". In particular, the supplemental guides being prepared to give added value to the GUM are outlined. The guides will cover (a) numerical methods for the propagation of distributions, (b) models with more than one measurand, (c) conformity assessment and (d) modelling.
Keywords: Uncertainty; Guide to the expression of uncertainty in measurement; Law of propagation of uncertainty; Supplemental guides; Propagation of distributions