Results of interlaboratory comparisons and proficiency tests are a significant parameter for the calibration testing laboratories assuring quality test results performed by those laboratories. If want to demonstrate that they operate according management system, technically competent can produce valid in calibrations perform their customers, general requirements must meet defined ISO/IEC 17025:...

An interlaboratory comparison was organised by JRC-IRMM among environmental radioactivity monitoring laboratories for the determination of gross alpha/beta activity concentration in drinking water. Independent standard methods were used for the reference value determination. The performance of participating laboratories was evaluated with respect to the reference values using relative deviation...

Bovine blood is used frequently as control material in interlaboratory comparisons for blood-lead analysis, but an erythrocyte protoporphyrin control material is needed. We present data on the rate of changes in blood lead and erythrocyte protoporphyrin in steers fed lead acetate. We also show, by comparison of fluorescence spectra with those of known compounds, that most of the porphyrin in le...

As food legislation calls for methods of control, reliable analytical methods have to be available to make the enforcement of regulations possible. The reliability of analysis data can be improved through the use of methods that fulfil certain performance criteria (demonstrated in interlaboratory studies) and the application of analytical quality assurance (AQA) procedures is recommended, inclu...

PURPOSE: The purpose of this technical note is to report the results of studies comparing two cell-based assays as screening tools for dioxins and related compounds in sediments. The Reuber H4IIE rat hepatoma cell line and the recombinant 101L human hepatoma cell line were used to assay 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) toxic equivalents (TEQs) in split samples of the same sediment ext...

I describe a micro-scale method for determining lead in whole blood by utilizing a graphite furnace. Sample pretreatment consists of fivefold dilution with a dilute surfactant. The method is directly calibrated with lead standards prepared in dilute HNO3. To eliminate a small, nonspecific absorption signal from the blood matrix, simultaneous background correction is used. Interlaboratory co...

This manuscript presents an interlaboratory comparison of OC/EC analysis using 2 different thermal protocols and the Sunset carbon analyzer. The study is interesting as it appears to be the first one where all participants use the same thermal protocols. Also discussions on TC/OC/EC quantification in the community are going on for years and any intercomparison is a welcome addition to existing ...

Determining the degree of equivalence participating laboratories from results measurement comparisons still prompts discussions among metrologists, especially where uncertainties have been underestimated. This paper expands on a solution to problem issued in 2020 by Journal Analytical and Bioanalytical Chemistry. The example illustrates an approach consensus-building based Bayesian selection st...

A statistical approach to link the results of interlaboratory comparisons with linear trends is proposed. This approach can be applied to the case that the comparison artifacts have the same nominal values or the measured quantities have the same magnitudes. The degrees of equivalence between the pairs of National Metrology Institutes that have not participated in the same comparisons, and thei...