Jong APJM de ,
Hartog RS den ,
Hijman WC ,
Boer AC den ,
Marsman JA ,
Liem AKD
18 p
in Dutch
1993
Toon Nederlands
English Abstract This report summarizes the results of a first European
interlaboratory calibration study by the Bureau of Reference (BCR) of the
European Commission on the analysis of PCDD/Fs in milk powder by
laboratories of the EC. In total nine laboratories from Belgium (1),
Germany (3), England (1) and the Netherlands (4) and two laboratories from
Sweden and Finland, respectively, have completed the study. Ten other
laboratories, who initially agreed with participation, have not submitted
their results. The study comprised of a comparison of the own standards of
laboratories with a common standard of the BCR and the analysis of PCDD/Fs
in an authentic and two spiked milk powders samples with levels between the
background level and five times this level in cow's milk. The overall
analytical results by all participant laboratories showed a considerable
large variation, both in the quantified amounts in the common standard and
the levels in three milk powder samples. Results of about one quarter of
laboratories differed significantly the means, whereas the results of the
remaining participants agreed well within acceptable limits (+- 25%). In
general results of RIVM were close to the means. The within-laboratory
reproducibility of RIVM was on average within 10%. The accuracy of the
method based on agreement with assigned values, was better than 90% on
average. Concentrations of native PCDD/Fs in standard mixture agreed on
average within 15% to that in the BCR standards. A comparison on the basis
of degree of experience of laboratories showed that, with a few exceptions,
a long-standing experience and access to state-of-the art GC/HRMS
instrumentation are obviously demanding conditions to be able to perform
reliable analysis of PCDD/Fs at the sub parts-per-trillion level in cow's
milk.
