Report on the third inter-laboratory comparison organised by the Community reference laboratory for polycyclic aromatic hydrocarbons : 15 + 1 EU priority PAHs in sausage meat and acetonitrile

This report presents the results of the 3rd inter-laboratory comparison (ILC) of the Community Reference Laboratory for Polycyclic Aromatic Hydrocarbons (PAHs) on the determination of the 15+1 EU priority PAHs in sausage meat and acetonitrile, which was conducted along the lines of the IUPAC International Harmonized Protocol for the Proficiency Testing of Analytical Chemical Laboratories. In agreement with the National Reference Laboratories, the test materials used in this exercise were a canned sausage meat preparation spiked with the 15+1 EU priority PAHs and a solution of the analytes in acetonitrile, respectively. The materials were prepared gravimetrically. The assigned concentration values of PAHs in sausage meat and in acetonitrile were calculated from the gravimetric preparation data. Only officially nominated National Reference Laboratories of the EU Member States and from countries covered by the Technical Assistance and Information Exchange programme of the European Commission were admitted as participants. However, from latter countries only one laboratory reported results. The participants were free to choose the method for the analysis of the materials. z-Scores were calculated for the sausage meat material from the analytes' contents based on gravimetrical preparation values and the participants reported "final result". The reported values of the laboratories for PAHs in acetonitrile were not rated. For the sausage meat material 89 % of the reported values lay within the 95 % confidence interval of the target standard deviation (z-scores ≤ |2|), indicating that most of the participating laboratories were performing satisfactorily with respect to internationally accepted standards. However, in some cases bias and/or a high variability were discovered, and some analytes consistently caused specific problems. It is therefore recommended to investigate this further.