Report on the 7th inter-laboratory comparison organised by the European Union Reference Laboratory for Polycyclic Aromatic Hydrocarbons : 15 + 1 EU priority PAHs in spiked olive oil and solvent solution

The European Union Reference Laboratory for PAHs (EU-RL-PAHs), operated by the Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), organises yearly one or more proficiency tests (PTs) within the scope of the Regulation (EC) 882/2004. The proficiency test here reported concerned the determination of the 15+1 EU priority polycyclic aromatic hydrocarbons (PAHs) in an olive oil test sample. Participants to these PT were National Reference Laboratories for PAHs (NRLs-PAHs) and EU official food control laboratories. The number of participants was 54. The PT was organised along the lines of the IUPAC Harmonised Protocol for the Proficiency Testing of Analytical Chemistry Laboratories. The test material used was olive oil spiked with a 15 + 1 EU priority PAHs and a solution of the target analytes in depending of the preference of the participants acetonitrile or toluene. The results from participants were rated with z-scores and zeta-scores. About 90 % of the reported results were attributed with z-scores with an absolute value of below two, which is the threshold for satisfactory performance.