Forgot your password?
New user?
New Window Opens on the Secret Life of Microbes: Scientists Develop First Microbial Profiles of Ecosystems
CAS announces the release of SciFinder Scholar for Mac OS X
Press Releases
Press Releases
| Check out our New Publishers' Select for Free Articles |
Accreditation and Quality Assurance: Journal for Quality, Comparability and Reliability in Chemical Measurement (v.6, #11)
Metrology is becoming the language of the (inter)national marketplace
by Paul De Bièvre; (pp. 451-451).
On the assessment of compliance with legal limits Part 1: signal and concentration domains by E. Desimoni; S. Mannino; B. Brunetti (pp. 452-458).
Taking into account the uncertainty of measurement when assessing compliance of a given sample with compositional specifications or statutory limits is an open question. Rigorous assessment should be performed within the signal domain, and by considering both α and β errors. Working within the concentration domain through a calibration function, which is affected by additional experimental uncertainties, involves a different degree of uncertainty and can sometimes lead to unreliable verdicts. The matter is discussed, and illustrated with the aid of some worked examples, each using multiple simulated data sets, obtained by adding an arbitrarily chosen Gaussian noise to representative response/concentration functional relationships.
Keywords: Keywords Compliance assessment; Concentration domain; Legal limit; Signal domain; Uncertainty of measurement; t-test; α and β errors
An intercomparison exercise for trace metal monitoring in oxygen-rich and anoxic Baltic waters by C. Pohl; D. Schmidt; K. Nagel; P. Freimann; U. Hennings; A. Jacobsen; U. Michel; A. Neubauer-Ziebarth; A. Schulz (pp. 459-465).
Seawater samples for a laboratory intercomparison of trace metal concentrations (Mn, Fe, Ni, Cu, Cd, Pb) in the dissolved (<0.4 µm filtered) and particle-bound phases as well as total and reactive Hg were collected in the Gotland Basin, a region in the Baltic Sea with trace metal gradients in the halocline and the redox boundary. Two laboratories took part in this exercise, each laboratory analysing samples from two vertical profiles collected using ”clean” sampling techniques. The hydrographic and hydrochemical situation was determined to characterise the water column and help interpret the results. An estimation of the conformity of the two laboratories was performed by comparing the results with international intercalibration exercises and certified reference materials. For all metals the characteristic vertical distribution and the concentration range of the data were comparable to other results published for the region. The concentration differences in the amount contents of Mn, Fe, Ni, Cu, Cd, Pb and Hg determined between both laboratories were better than the confidence intervals given by an ICES (International Council for the Exploration of the Sea) international comparison exercise for Baltic waters. Differences for Ni in the anoxic water body are attributed to the sulphidic matrix and their influence on the different methods used by the laboratories. For Pb and Hg the concentrations were near the detection limit of our methods, low level contamination was possibly responsible for the concentration differences. Small differences for dissolved Mn were attributed to different sampling techniques. We conclude that sampling and sample handling are still weak links in the trace metal analysis of anoxic seawater and that the analytical methods we used for this exercise are satisfactory for the accurate determination of Cd, Cu, Pb, Mn, Fe, and also for studying biogeochemical cycling of these trace metals in oxygen-rich and anoxic water bodies.
Keywords: Keywords Intercomparison exercise; Trace metals; Baltic Sea; Anoxic seawaters
Metrological value of participating in interlaboratory comparisons by I. Papadakis; P. D. P. Taylor (pp. 466-468).
Quality of chemical measurement is a central issue nowadays with social, political and economic implications. This paper aims to describe how interlaboratory comparisons (ILCs) can contribute towards better quality of chemical measurements. The importance of ILCs as well as the different types and the requirements for proper organization of ILCs are explained. The international structure and organization of metrology is given, highlighting the activities related to chemical measurements. Particularly the use of ILCs in the service of metrology in chemistry is highlighted. A very important discussion concerning ILCs is how they can (or cannot) establish traceability. The view of the authors is that traceability cannot, as such, be established through ILCs. On the other hand, participation in ILCs can clearly support the claims for quality measurements, as ILCs are experimental and objective demonstrations of measurement capability.
Keywords: Keywords Interlaboratory comparisons; Traceability; Quality; MRA; Metrology; CCQM
Guidance on equipment qualification of analytical instruments: UV-visible spectro (photo)meters (UV-Vis), September 2000
by D. G. Holcombe; Michael C. Boardman (pp. 468-478).
Quality movements in eastern European medical laboratories by A. Jabor (pp. 479-480).
The national efforts in quality management in different eastern European countries (Croatia, Czech Republic, Hungary, Poland, Russia, Romania, Slovakia, Slovenia) are described. The clinical chemistry domain is specifically analysed covering external quality systems, accreditation bodies and the normative background. The roles of government, professional and scientific bodies are mentioned. A detailed description of Czech Republic is given.
Keywords: Keywords Accreditation; Clinical chemistry; External quality systems; Quality management; Standards