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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.4, #1-2)
Some recent developments in reference methodology within the United Kingdom by T. Catterick; D. Craston; B. King; R. F. Walker; K. S. Webb (pp. 3-13).
The UK Valid Analytical Measurement Programme has pump-primed developments in chemical metrology, through a major project on reference methodology and reference materials. This paper provides an overview of developments during 1994–1997 and covers work on primary methods for trace inorganic and trace organic analysis, including the use of isotope dilution mass spectrometry; studies of sample pre-treatment, including digestion, extraction, and separation aimed at improving this weak link in the traceability chain; prioritisation, production and marketing of both pure substance and matrix reference materials; and international collaboration concerned with interlaboratory comparisons and the development of concepts, terminology and systems to underpin the international chemical measurement system. References are given to a number of papers covering specific parts of the programme.
Keywords: Key words Metrology; Primary methods; Reference materials; Traceability; Isotope dilution mass spectrometry
An alternative to the effective number of degrees of freedom by Alex Williams (pp. 14-17).
In order to calculate the expanded uncertainty when one or more of the components of the standard uncertainty is based on a small number of degrees of freedom, the ISO Guide recommends utilising the 'effective number of degrees of freedom'. Calculating and utilising the 'effective number of degrees of freedom' to obtain a confidence interval both depend upon approximations, which, however, are adequate for determining an expanded uncertainty. This paper puts forward an alternative and simpler approximation which is also adequate but which is much easier to apply than the multi-step process given in the ISO Guide.
Keywords: Key words Degrees of freedom; Expanded uncertainty
Quality assurance in clinical chemistry laboratories in the UK by Keith W. Davies (pp. 18-26).
Since the mid-1960s quality assurance in clinical chemistry has progressed from a need to define and improve precision and accuracy in analytical test procedures to an all-embracing process of assuring that the whole process of pre-analytical, analytical and post-analytical phases of handling patient samples is managed effectively and efficiently. Automated and computer-controlled equipment has reduced many of the analytical errors, in particular in imprecision, that were present in manual analysis. New management techniques have been developed to control the quality and appropriateness of results. Developments in internal quality control and external quality assessment procedures have enabled laboratories to continually improve the quality of assays. Laboratory accreditation and external quality assessment scheme accreditation have ensured that peer review and peer pressure have been applied to both laboratory and external quality assessment scheme performance. As the NHS reviews its priorities and places more emphasis on primary care provider demands, hospital laboratories will of necessity assist with near patient testing outside the laboratory. This will provide new challenges to the quality of the service provided.
Keywords: Key words Quality assurance; Internal quality control; External quality assessment; Demand Management; Accreditation
Assessment of compliance of analytical results with regulatory or specification limits by B King (pp. 27-30).
In some cases the compliance of a measurement result with a limit value will be unclear and a 'judgment' is required based on agreed criteria. Recent developments in the estimation of measurement uncertainty have opened up the possibility of a more rational approach to such problems. This paper briefly reviews some of the issues and current practices and suggests a pragmatic way forward.
Keywords: Key words Compliance decisions; Regulatory limits; Specification; limits; Measurement uncertainty
Laboratory accreditation – where next? by Alex Williams (pp. 31-32).
Laboratory accreditation is now well established and can justly claim to have had a beneficial impact on the quality of the services provided by accredited laboratories. However, the needs of laboratories and their customers are continually evolving. It is necessary for accreditation practices to keep abreast of these changing requirements if they are to continue to be of benefit to laboratories and their customers. This paper gives a brief review of current accreditation practice and suggests some changes that should be made to help laboratories meet the demands made on them by their customers.
Keywords: Key words Accreditation; Quality; Value for money
Calibration bias in the determination of polynuclear aromatic hydrocarbons in water by M. Gardner; Iain Taylor (pp. 33-36).
We present the results of an investigative interlaboratory test to determine the reasons for poor agreement between data from different laboratories for the determination of polynuclear aromatic hydrocarbons in water.
Keywords: Key words Analytical quality control; Water analysis; Accuracy; Polynuclear aromatic hydrocarbons
Basic skills of analytical chemistry: do we take too much for granted? by Elizabeth Prichard (pp. 37-39).
This paper examines some questions which arose from the competition organised by the Laboratory of the Government Chemist in conjunction with the Nuffield Curriculum Projects Centre and from years of experience in higher education. It goes on to indicate the ways that some of these problems may be tackled.
Keywords: Key words Valid analytical measurements; Proficiency testing; Key skills; Titration; Practical competence
Accreditation in the United Kingdom: responding to needs or 'changing the goalposts'? by Jane Beaumont (pp. 39-42).
The requirements for establishing the competence of organisations involved in testing, calibration, certification and inspection, and the criteria for their assessment and accreditation are specified in international guides and European standards. As these guides and standards are intended for use by a range of organisations and accreditation bodies, operating in different disciplines, they are written in general terms in order to be widely applicable. It follows that some interpretation of the requirements is needed in order to address the different ways in which both organisations and accreditation bodies operate. This may be seen by accredited organisations as providing an opportunity for accreditation bodies to 'change the goalposts'; the needs of these organisations and of their clients must be accommodated as far as possible, without diminishing the value of, or undermining confidence in, accreditation. The United Kingdom Accreditation Service has been listening to its customers, reviewing its activities and is offering a more flexible pragmatic approach to assessment and accreditation; some of the new developments are described.
Keywords: Key words Accreditation; United Kingdom Accreditation Service
It is never too early to introduce measurement and quality concepts: a proficiency test competition for schools and colleges by J. A. Hunt; Janet Taylor (pp. 43-45).
This paper describes how the LGC and the Nuffield Curriculum Projects Centre set up an analysis competition for 16- to 19-year-old students. The competition was based on the procedure for proficiency testing. The results and reports give some insight into current standards of teaching and learning about analytical procedures and the treatment of uncertainty in courses at this level. The outcomes justify the production of a good-practice guide for teachers so that they can introduce concepts of valid analytical measurement into pre-university courses.
Keywords: Key words Valid analytical measurement; Proficiency testing; Competition; School/college education
Marketing Valid Analytical Measurement by A. Gillespie; Sue Upton (pp. 45-49).
The Valid Analytical Measurement (VAM) programme was set up by the Department of Trade and Industry as part of its support for the UK National Measurement System. This paper gives an overview of the VAM programme together with a description of the principles on which valid analytical measurement should be based. This is followed by a description of the work that has been carried out to market the results of the VAM programme to the analytical community.
Keywords: Key words Valid analytical measurements; Marketing technology; Technology transfer
The development and application of guidance on EQ of analytical instruments: High performance liquid chromatography by P. Bedson; David Rudd (pp. 50-62).
This paper describes the development and application of guidance on EQ (EQ) of high performance liquid chromatography instruments. EQ is a formal process that provides documented evidence that an instrument is fit for its intended purpose and kept in a state of maintenance and calibration consistent with its use.
Keywords: Key words EQ; Design qualification; Installation qualification; Operational qualification; Performance qualification; High performance liquid chromatography