Towards Less Manipulated Reference Materials for Food and Environmental Analysis

The need for reliable and comparable analytical data in food and environmental monitoring stipulate the need for "new/alternative" types of reference materials matching more closely real world samples. Matrix certified reference materials are required in the validation of methods of analyses of real environmental samples, because matrix effects may result in bias of the analytical results. The study was designed to assess the equivalence between three different processing options for the production of food/environmental reference materials. Finding an appropriate analyte/matrix combination was the first step. A stable analyte, PCBs (polychlorinated biphenyls) was chosen in this case, in order not to complicate the study too much by choosing analytes that could potentially degrade. A fatty fish such as mackerel was chosen as in such matrices the naturally occurring levels of PCBs are sufficiently high not to create too many difficulties for the quantification. Spiking should be avoided because this would compromise the closeness to a real sample and would complicate the homogeneity of the fresh material. The fatty matrix is also a challenge in the processing, as a homogeneous distribution of the fatty parts has to be ensured. PCBs 28, 52, 101, 118, 138, 153 and 180 have been selected because they are frequently determined. They show a high occurrence in environmental and waste samples and represent both lower and higher chlorinated congeners. This paper summarises the protocol used to determine the homogeneity of the three material presentations. And the results from the analyses carried out to measure the PCB content of batches stored at different conditions. Evaluation of the suitability of the test materials will be performed with respect to its behaviour under different storage conditions.JRC.DG.D.2-Reference material