This report describes the production of IRMM-427, a fish material certified for the mass fraction of perfluoroalkyl substances (PFASs). The material was produced following ISO Guide 34:2009.
The starting material for the CRM is naturally contaminated pike-perch fillets originating from the rivers Nieuwe Merwede and Amer in the Netherlands. After converting the tissue into a paste, the material was sterilized by autoclavation at 120 °C and the jars stored at 18 °C. Between-unit homogeneity was quantified and stability during dispatch and storage were assessed in accordance with ISO Guide 35:2006. Within-unit homogeneity was quantified to determine the minimum sample intake.
The material was characterised by an intercomparison among laboratories of demonstrated competence and in most cases adhering to ISO/IEC 17025:2005. Technically invalid results were removed but no outlier was eliminated on statistical grounds only.
Uncertainties of the certified values were estimated in compliance with the Guide to the Expression of Uncertainty in Measurement (GUM) and include uncertainties related to possible inhomogeneity, instability and characterisation.
The material is intended for the quality control and assessment of method performance. As any reference material, it can also be used for control charts or validation studies. The CRM is available in glass jars containing approximately 35 g of fish paste. The minimum amount of sample to be used is 1 g.