IMEP-32 : determination of inorganic arsenic in animal feed of marine origin (a collaborative trial report)

A collaborative study, IMEP-32, was conducted in accordance with international protocols to determine the performance characteristics of an analytical method for the determination of inorganic arsenic in animal feed of marine origin. The method would support Directive No 2002/32/EC of the European Parliament and the Council on undesirable substances in animal feed where it is indicated that "Upon request of the competent authorities, the responsible operator must perform an analysis to demonstrate that the content of inorganic arsenic is lower than 2 ppm". The method is based on solid phase extraction (SPE) separation of inorganic arsenic from organoarsenic compounds followed by detection with hydride generation atomic absorption spectrometry (HG-AAS). The collaborative study investigated different types of samples of marine origin, including complete feed (unspiked and spiked), fish meal (unspiked and spiked), fish fillet (spiked) and a lobster hepatopancreas (unspiked). In total seven samples were investigated within the concentration range of 0.07 - 2.6 mg kg-1. The test samples were dispatched to 23 laboratories in 12 different countries. Nineteen participants reported results. The performance characteristics are presented in this report. All method performance characteristics obtained in the frame of this collaborative trial indicates that the proposed SPE-HGAAS standard method is fit for the intended analytical purpose.