Report of the interlaboratory comparison : ILC01 2011- Formaldehyde in food contact migration solution

This report presents the results of the Inter-laboratory comparison (ILC) organise by the EURL-FCM, Ispra (Italy), which focus on the quantification of formaldehyde in migration solutions of 3% acetic acid from food contact materials. The test materials used for preparation of the migration solutions were melamine kitchenware (spoons) containing formaldehyde. The EURL prepared and distributed three concentration levels of migration solution. The general aim of the exercise was to assess the proficiency of the official control laboratories and consequently the participants were free to use any analytical method of their choice, however CEN 13130-23 method was suggested. There were 62 participants to whom samples were dispatched (27 national reference laboratories (NRLs) + 35 national control laboratories) and 61 of which submitted results. The homogeneity and stability studies were performed by the EURL-FCM laboratory. The assigned values were obtained after applying the robust statistics to the results of the participants. Participants were invited to report four results for each concentration level. This was done by most of the participants. Laboratory results were rated with z-scores in accordance with ISO 13528 [1], standard deviations for proficiency assessment (also called target standard deviations) were set based on Horwitz equation. As a conclusion of the ILC exercise on the quantification of formaldehyde in the migration solution of kitchenware in 3% acetic acid, this ILC showed that the participation in the ILC was satisfactory regarding the number of the participating laboratories. From the EURL-NRL network all 27 laboratories reported results. One guest did not send any results. 52 laboratories (more than 85%) including all NRLs had all results successful and for 8 participants all results were unsatisfactory. Data were proceed a second time separately grouped by the two sample preparation methods CRchromotropic acid and AA-acetyl acetone. Statistical T-test shows that the results obtained using CR method do not differ significantly from the results obtained by second - AA method. These two methods are interchangeable.