Feed premix: a difficult matrix for the accurate determination of trace elements – the outcome of IMEP-114 and IMEP-36

Abstract

This paper presents the outcome of two proficiency tests (IMEP-114/36) running in parallel, which focused on the determination of total As, Cd, Pb, Hg and Sn in feed premixes. Both exercises aimed to test the performance of laboratories measuring trace elements in feed, in compliance with Directive 2002/32/EC of the European Parliament and of the Council on undesirable substances in animal feed. IMEP-114 was run for the European Union National Reference Laboratories, while IMEP-36 was open to all food control laboratories that wished to participate. In total 80 laboratories from 37 countries registered to both proficiency tests, from which 75 laboratories reported results. The test material used in this exercise was commercially available feed premix, which was processed, bottled, labelled and dispatched to participants. The performance of the participating laboratories was similar in both proficiency tests and was very good in the case of total Cd and less satisfactory for total As and total Pb. For total Sn only one-third of the participants reported results, from which 33% performed satisfactorily. Thirty-four participants reported results for total Hg, although the expert laboratories stated that the mass fraction for that measurand was below the limit of detection of the method used. An evaluation of the reasons that could be at the basis of unsatisfactory results has been carried out and is presented here.

European analytical column

“…Also, when it comes to practical application by laboratories involved in routine analysis, the situation has improved a great deal during the past decade. Nevertheless, challenges still remain, as evidenced by, for example, discrepancies between participant results in ILCs [12][13][14]. The aim of this contribution is to review briefly why this is so and to give some guidance on the most important MiC activities for any laboratory.…”

European Analytical Column No. 43

“…Also, when it comes to practical application by laboratories involved in routine analysis, the situation has improved a great deal during the last decade. Nevertheless, challenges still remain as evidenced by, for example, discrepancies between the results of participants in ILCs [10][11][12]. The aim of this contribution is to review briefly why this is so and give some guidance on the most important MiC activities for any laboratory.…”