European intercomparison study for the determination of the fumonisins content in two maize materials

The results of an intercomparison study for the analysis of fumonisin B1 (FB1) and fumonisin B2 (FB2) in a contaminated maize material (Maize B, containing approximately 2 micrograms/g FB1 and 1 micrograms/g FB2) and its 'blank' counterpart (Maize A, containing less than 20 ng/g FB1 and FB2) are reported. Maize materials were distributed in 60 g sachets, submitted to gamma-irradiation at 15 kGy, and distributed to participating laboratories. The study was carried out by 24 European laboratories, most of which have national or international responsibilities for food/feed quality control. Participants used basically one method with some modifications, based on clean-up through SAX minicolumn and reversed phase HPLC with fluorescence detection of the OPA-fumonisin derivatives. The intercomparison study generated data (after correction for recoveries) with repeatability and reproducibility levels of: RSDr = 10% and RSDR = 11% for FB1; RSDr = 11% and RDSR = 13% for FB2. The recoveries obtained by most participants were considered low (70% for FB1 and 69% for FB2), being considerably affected by the extraction mode. Average recoveries for laboratories using blending were 62% and 60%, whereas for laboratories using shaking they were 85% and 86% for FB1 and FB2, respectively. The day-to-day- data showed a between-day, within-laboratory repeatability lower than 15% (CV < 15%) for FB1 for all laboratories, whereas only three laboratories obtained a between-day, within-laboratory reproducibility higher than 15% (CV > 15%) for FB2.