| Abstract: | A systematic quality control programme carried out by a number of laboratories from the European Union and from EFTA countries
is described. The programme was designated to improve the analytical state of the art in the determination of selected chlorinated
benzenes and chlorinated phenols in different environmental matrices. To that end a stepwise interlaboratory study approach
was chosen, analysing, in consecutive order, a clean extract of soil, a raw extract and the soil itself. Eight analytes were
selected for the study, i.e. three chlorobenzenes and five chlorophenols. During the programme significant improvements in
analytical performance were achieved, as shown by a decrease in within-laboratory coeffficients of variation as well as by
acceptable coefficients of variation in the mean value of laboratory means of all analytes in the final matrix analysed, i.e.
a natural soil. The results of the programme prompted the European Union to embark upon a pentachlorophenol interlaboratory
certification study to produce an industrial soil candidate Certified Reference Material (CRM) 1].
Received: 28 August 1997 / Revised: 15 October 1997 / Accepted: 21 October 1997 |
