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Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.8, #11)
Future direction for measurement, testing and conformity assessment by Jarl Forstén (pp. 498-504).
Measurement and testing are of fundamental importance to science, technology and the economy. There is no science without measurements, no quality without testing and no global market without standards. This article tries to look into the future for the testing community. Based on the anticipated changes in the environment for the testing activities a prediction of the coming technical development as well as acceptance of test results is given. Also the future of accreditation is discussed.
Keywords: Measurement and testing; Global development; Testing quality; Accreditation
Observation of a combined dilution and salting effect in buffers under conditions of high dilution and high ionic strength by Richard J. C. Brown; Martin J. T. Milton (pp. 505-510).
The pH value of buffer solutions is crucially dependent on the relative concentrations of all species in solution. The addition of water or neutral salt can have a significant effect on the pH of a buffer solution. This study examines the magnitude of the "dilution effect" and the "salt effect" for several commonly used inorganic and biological buffers. Novel data are obtained for the change in pH observed upon dilution or addition of neutral salt to these buffers which add to, complement and extend existing literature values. The validity of considering the dilution and salt effects as a combined ionic strength effect is also considered as well as the ability of the pH measuring device to perform valid measurements in these extreme conditions.
Keywords: pH; Buffers; High ionic strength; Dilution effect
How to interpret information from proficiency test exercises concerning the relative performance of accredited laboratories by L. Cortez; A. Duarte; A. Hundewadt; A. Schmidt; B. Steffen; D. Tholen; H. Fostel; I. Papadakis; M. G. del Monte; N. Boley; P. M. van Berkel (pp. 511-513).
If the results from various proficiency tests are used to compare the performance of accredited and non-accredited laboratories, great care must be taken not to come to contradicting conclusions when interpreting them. This paper intends to draw the attention to various aspects that should be taken into account when trying to make conclusions from the relative performance of accredited laboratories in proficiency testing.
Keywords: Proficiency test exercises; Accredited laboratories; Relative performance
Practical assessment of the suitability of IQC control materials in haemocytometry based on biologic goals by Milan Skitek (pp. 514-519).
We have assessed short and long-term imprecision goals based on biological variation in haemocytometry through internal quality control (IQC) for the following parameters: white blood cell (WBC), red blood cell (RBC) and platelet (Plt) counts, concentration of haemoglobin (Hb) and mean cell volume (MCV). The attainment of short-term imprecision goals in the IQC system with our own and commercial control blood (between-day control) presents problem for MCV, where minimum performance is achievable, the analytical coefficient of variation (CV) being less than three-quarter of the average within-subject variation (CV I), i.e. CV<0.75 CV I. For the other four parameters desirable performance (CV<0.50 CV I) and even optimum performance—CV<0.25 CV I (for WBC and Hb) is achievable. The long-term desirable imprecision goals (CV L) based on within- and between-subject variation (CV G) seem to be too loose. However optimum performance % MathType!Translator!2!1!AMS LaTeX.tdl!TeX -- AMS-LaTeX! % MathType!MTEF!2!1!+- % feaafeart1ev1aaatCvAUfeBSjuyZL2yd9gzLbvyNv2CaerbuLwBLn % hiov2DGi1BTfMBaeXatLxBI9gBaerbd9wDYLwzYbItLDharqqtubsr % 4rNCHbGeaGqiVu0Je9sqqrpepC0xbbL8F4rqqrFfpeea0xe9Lq-Jc9 % vqaqpepm0xbba9pwe9Q8fs0-yqaqpepae9pg0FirpepeKkFr0xfr-x % fr-xb9adbaqaaeGaciGaaiaabeqaamaabaabaaGcbaWaaeWaaeaaca % WGdbGaamOvamaaBaaaleaacaWGmbaabeaakiabgYda8iaaicdacaGG % UaGaaGOmaiaaiwdadaWadaqaaiaadoeacaWGwbWaa0baaSqaaiaadM % eaaeaacaaIYaaaaOGaey4kaSIaam4qaiaadAfadaqhaaWcbaGaam4r % aaqaaiaaikdaaaaakiaawUfacaGLDbaadaahaaWcbeqaamaalyaaba % GaaGymaaqaaiaaikdaaaaaaaGccaGLOaGaayzkaaaaaa!4968! $$ {left( {CV_{L} < 0.25{left[ {CV^{2}_{I} + CV^{2}_{G} }
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ight)} $$ is attainable for all five basic haemocytometry parameters. In the IQC system with retained patient specimens (within-day control), short-term imprecision goals for optimum performance are surpassed for WBC and Hb and desirable performance is achieved for RBC, MCV and Plt.
Keywords: Multichannel haematological analyser; Internal quality control; Biological variation; Whole blood control
GUM Workbench as measurement modelling and uncertainty estimation software: experience at University of Tartu by Lauri Jalukse; Eve Koort; Julia Traks; Ivo Leito (pp. 520-522).
Experience with the GUM Workbench software at the University of Tartu is described. Although primarily meant for measurement uncertainty estimation, the scope of use of GUM Workbench is significantly broader: it allows one to analyse one's measurement procedure and to find out how to improve it. The most important features of the software in addition to providing the measurement uncertainty for a specific measurement procedure are the possibilities of finding out what are the main contributors to the measurement uncertainty and presenting the whole measurement procedure—description, equations, data and comments—in a very clear and accessible way. The usefulness of these features in teaching is specifically stressed.
Keywords: Measurement uncertainty; ISO method for uncertainty estimation; Uncertainty budget; Modelling of measurements.
Proficiency tests for pharmaceuticals in different waters by Manfred Sengl; Sonja Krezmer (pp. 523-529).
To date there are no German or international standards for the analysis of pharmaceuticals in waters. The efficiency of the analytical methods—predominantly LC-MS/MS and GC-MS—used for trace analysis of pharmaceuticals is proved for the first time by proficiency tests using natural waters.Two proficiency tests for up to 11 different groups of pharmaceuticals in river water and waste water were carried out in 2000 (28 participants) and 2002 (20 participants). The spiking concentrations were 60–800 ng/L for surface water and 80–1280 ng/L for waste water. For most determinants good recovery rates (80–120%) and variations (around 35% for surface water and 50% for waste water) were reported.
Keywords: Proficiency test; Pharmaceuticals; Surface water; Waste water
Traceability without uncertainty: current situation in the pharmaceutical industry by Ilya Kuselman; Alexander Weisman; Wolfhard Wegscheider (pp. 530-531).
The current situation in the pharmaceutical industry is discussed, when the traceability of measurement (analytical) results to certified values of pharmacopoeial reference standards is required, without evaluating their uncertainties. It is shown that the evaluation of measurement uncertainty is necessary for understanding the level of confidence of the analytical results and their comparability, particularly during preparation and characterisation of the reference standards.
Keywords: Traceability; Measurement uncertainty; Reference materials; Quality of analytical results