Inter-laboratory comparison study on the determination of primary aromatic amines in cold water extracts of coloured paper napkins.

To evaluate the competence in the analysis of primary aromatic amines (PAAs) in cold water extracts from napkins, an inter-laboratory comparison study was conducted with 19 participating laboratories. Two cold water extracts spiked at two different PAA concentration levels, each containing four different PAAs (aniline, o-toluidine, 2,4-dimethylaniline and o-anisidine) and, additionally, four different napkins containing one of the PAAs each were distributed between the laboratories. In this exercise, the influence of different parameters in the preparation of cold water extracts from napkins according to the European Norm (EN) 645 was also investigated. For the already spiked cold water extracts and the napkins, 88% and 77% of the results were satisfactory with zU-scores of ≤ |2|. The Horwitz ratio (HorRat) values for the spiked cold water extracts were in the range of 0.48-1.25. For the napkins, HorRat values were in the range of 1.261.91, whereas the lowest assigned value was 0.97 µg l(-1) (o-toluidine). Thus, the results show that preparation and instrumental analysis of PAAs in cold water extracts from napkins according to EN 645 has been well established.