Report of the follow-up collaborative study : determination of the sum of fumonisin B1 and B2 in compound animal feed and maize by immunoaffinity column clean-up and high performance liquid chromatography with fluorometric detection

A collaborative study to validate a method to determine the sum of Fumonisin B1 (FB1) and B2 (FB2) in compound animal feed and maize by immunoaffinity column clean-up and High Performance Liquid Chromatography with Fluorometric Detection (HPLC-FLD) was conducted by the Joint Research Centre - Institute for Reference Materials and Measurements with the participation of 16 laboratories of 12 Member States of the European Union. The method consisted of extraction of the Fumonisins from the sample with 50 % methanol in phosphatebuffered saline, clean-up with immunoaffinity columns, and detection of the o-phtaldialdehyde derivatives after either pre- or post-column derivatisation with HPLC-FLD. Five materials, consisting of compound animal feed and maize, were tested. Three of the materials were naturally contaminated, and two were naturally contaminated and additionally spiked. The contamination levels ranged from 3 to 16 mg/kg for the sum mass fraction of FB1 and FB2. Four laboratories had to be excluded from the evaluation because of non-compliance. For the remaining 12 laboratories repeatability and reproducibility were computed using robust statistical methods. Relative repeatability and reproducibility standard deviations of 2.0 to 5.3 %, and 15 to 20%, respectively, were found. Horwitz ratios ranged from 1.2 to 1.9 and were all acceptable. We deem the method as fit for the purpose of enforcing recommended maximum levels of the sum of Fumonisin B1 and B2 in animal compound feed, and maize intended for animal feed, and have submitted it to the European Committee for Standardisation (CEN)/ Technical Committee (TC) 327 Animal feeding stuffs.