This report presents the results of the proficiency test IMEP-36 which focused on the determination of total Cd, Pb, As, Hg and Sn in feed premixes according to Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed. Fifty laboratories from 22 countries registered to the exercise of which 45 reported results and answered the respective questionnaire.
Laboratories were asked to perform two or three independent measurements and to report the mean, the associated uncertainty, the coverage factor of the associated uncertainty and the technique used to perform the measurements. Laboratory results were rated using z- and ζ-scores (zeta-scores) in accordance with ISO 13528. The assigned values (Xref) for the measurands were determined as the mean of the values reported by two expert laboratories both of them National Metrology Institutes (NMI).
The results obtained by the participants were optimum in the case of total Cd and less satisfactory for total As and total Pb. For total Sn 16 participants reported results, from which one third scored satisfactorily. Twenty one participants reported results for total Hg although, the expert laboratories reported that the mass fraction for that measurand was below their limit of detection. Hence, no scoring was provided for total Hg.JRC.D.5-Standards for Food Bioscienc
