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.14, #6)
Accreditation of (chemical) measurement laboratories is also about verifying the implementation of metrological principles in (chemical) measurement
by Paul De Bièvre (pp. 293-294).
Simple principles for metrology in chemistry: identifying and counting by Gary Price; Paul De Bièvre (pp. 295-305).
We examine the problem of quantitative chemical measurement for well-identified substances, discuss the quantity called ‘amount of substance’, the means of expressing it, and its physical SI unit the mole. The everyday quantity which is a number of entities may be measured by the performance of two operations (identification and counting), the results of which may be communicated with two items of information (their name and the number of entities). We distinguish nominal, ordinal, interval and ratio scales of measurement and apply these to counting, referring to ordinal and cardinal numbers and Helmholtz’ analysis of measurement. Counting may be by direct serial numeration, direct parallel numeration, or comparative numeration. We discuss the limitations of serial numeration, the possibilities of parallel numeration, and the advantages of comparative numeration where a unit for counting in multiples (such as the analyst’s mole) may be used to define a scale on which equal numbers of objects correspond to equal values of some other physical quantity. We conclude that the numeration of very large numbers of objects is readily achieved but with unavoidable uncertainty, using operations which compare numbers of entities either to numbers of other entities or to some other quantity which accurately models numbers of entities.
Keywords: Metrology in chemistry; Mole; Measurement scales; Amount of substance
Visualisation of proficiency test exercise results in Kiri plots by A. V. Harms (pp. 307-311).
A novel graphical method (‘Kiri plots’) for the presentation of proficiency test exercise results is presented. The Kiri plot visualises the evaluation of the proficiency test results based on three statistical tests (the z score, the zeta score and the relative uncertainty outlier test) by defining six zones including a central “in agreement” zone.
Keywords: Proficiency test exercise; Uncertainty; Data evaluation
Uncertainty budget for the temperature realisation with a triple-fixed-point blackbody by Marc Schalles (pp. 313-317).
A new triple-fixed-point blackbody for the calibration of radiation thermometers at fixed-point temperatures in the range of 232–660 °C was developed at the Ilmenau University of Technology. The fixed-point temperatures T fp were measured by means of a transfer radiation thermometer and an uncertainty budget for T fp was established, whose components differ from typical uncertainty budgets of single-fixed-point blackbodies.
Keywords: Calibration; Radiation thermometer; Triple-fixed-point blackbody
Interlaboratory studies on wastewater toxicity using Daphnia magna by Magda Cotman; Andreja Drolc; Tatjana Tišler (pp. 319-327).
In order to verify the quality of biological measurements, the National Institute of Chemistry in Slovenia is regularly organizing interlaboratory comparisons to estimate the analytical precision of different laboratories using the same test and to determine if statistically significant differences exist between results. Several interlaboratory trials named “ILC-Waste Water” (ILC-WW) were organized in the last 7 years. Acute toxicity testing with Daphnia magna mobility inhibition assay (ISO 6341) was included in eight successive rounds and about 20 laboratories from Slovenia and a few adjacent countries took part in each study with two samples (T1 and T2) at two different concentration levels. Variation coefficients of the mean 24 h EC50s were determined for each exercise and the evaluation of the interlaboratory variability was analysed. Comparisons were also made of the results and the variability laboratories using organisms taken from laboratory cultures versus those who used daphnias hatched from dormant eggs (Daphtoxkits).
Keywords: Acute toxicity test; Daphnia magna ; Interlaboratory comparison
The establishment of a quality evaluation system of reference materials by Xiaohua Lu; Hongmei Li; Fanmin Meng; Jie Ji (pp. 329-332).
Reference materials have been applied widely to ensure the traceability, comparability and reliability of measurement results. To achieve this purpose, the quality of reference materials (RMs) themselves is surely an important aspect to be pay attention to. A quality evaluation system of RMs has been established through the project “The National Sharing Platform of Reference Materials” in China to give a reliable assessment on the quality of RMs from various sources including the accuracy and comparability of their property values, which is very useful to promote the appropriate selecting and using of RMs in China. Through the application of National Metrology Institute calibration and measurement capabilities on the basis of the international mutual recognition arrangement, it can also provide a powerful supplement to the current activities such as the accreditation of RM producers in the construction of a global harmonized quality control and assurance system of RMs.
Keywords: Reference material; Quality; Comparability; Accuracy
Report of the 31st meeting of ISO/REMCO
by Adriaan M. H. van der Veen; Hendrik Emons; Ales Fajgelj; Yu Yadong; Stéphane Sauvage (pp. 333-335).
European analytical column no. 37 (January 2009) Division of Analytical Chemistry (DAC) of the European Association for Chemical and Molecular Sciences (EuCheMS)
by Bo Karlberg; Manfred Grasserbauer; Jens E. T. Andersen (pp. 337-340).
Report of the TrainMiC® Convention, held in Celje, Slovenia (10–14 January 2009) by Philip D. P. Taylor; Ewa Bulska; Steluta Duta; Nineta Majcen; Ioannis Papadakis; Lutgart Van Nevel; Emilia Vassileva (pp. 343-346).
The main aim of the TrainMiC® Convention was to gather TrainMiC® authorized trainers from all 19 countries involved in this programme. About 90% of all authorized TrainMiC® trainers assembled at this Convention, which shows the interest in and usefulness of the TrainMiC® system. The role and position of the authorized trainers was formally recognized by the introduction of a User License Agreement (based on a European Commission Decision, concerning the granting of a copyright license for TrainMiC® trainers, 17 December 2008) which was signed by the attendants. Participants received an update on the training material and could give their input and suggestions for improvement, which will then be discussed and reviewed by the Editorial Board. It is this which makes TrainMiC® a truly devolved and living system which can adapt itself. Participants also gave their input on how to further develop TrainMiC® from a system point of view. Topics included better focus on priority sectors, improved course interactivity, further improvement of pedagogical skills of authorized trainers, better marketing and identifying multiple sources of funding.