International archives of occupational and environmental health
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Int Arch Occup Environ Health · Mar 2001
Multicenter Study Comparative StudyFurther round-robin tests to improve the comparability between laboratories of the measurement of carbon in diesel soot and in environmental samples.
An informal European coordination group organized two round-robin tests on filters collected from environmental, workplace and diluted diesel emissions. Previous inter-laboratory comparisons have shown that experimental samples give reasonably good results in terms of the dispersion around the mean, from all the participating laboratories. However, there were significant differences between the laboratories owing to a narrow distribution of the results within a single laboratory. In order to gain a better understanding of the differences obtained between the laboratories, it was decided to carry out more round-robin tests and to investigate further the possible factors which may influence the results. ⋯ It was expected that a significant improvement would be seen in the inter-laboratory dispersion by the use of a common standardized thermal desorption program, but the objectives of these RRTs were only partly reached. This paper provides new information that will be useful in the elaboration of a standardized procedure for the European Normalisation Centre (CEN TC 137 WG2--General requirements for measuring procedures).