Validation of an Analytical Method to Determine the Content of Fumonisins in Baby Food, Breakfast Cereals and Animal Feed

摘要

An inter-laboratory comparison was carried out to evaluate the effectiveness of a method based on immunoaffinity column clean-up followed by derivatisation and high performance liquid chromatography with fluorimetric quantification (HPLC-FL). The method was tested for the determination of Fumonisins B1 and B2 (FB1 & FB2) in baby food, breakfast cereals and animal feed to monitor compliance with limits according to Regulation 1881/2006/EC and Recommendation 576/2006/EC. The test portion of the sample was extracted with methanol:water. The sample extract was filtered, diluted, passed over an immunoaffinity column for clean-up and evaporated. The redissolved and purified eluate was separated and determined by reverse-phase high performance liquid chromatography (HPLC) and fluorescence detection after the fumonisins had been derivatised to their fluorescent isoindols in the presence of o-phthaldehyde and a thiol-coupling reagent with either pre- or post-column derivatisation.Baby food, breakfast cereal and animal feed samples, both blank and naturally contaminated with FB1 and FB2, were sent to 40 laboratories from 19 EU Member States, and a laboratory in Uruguay. For recovery determination extra test portions of the blank samples were to be spiked by the participants at levels of 135 µg/kg for the sum of FB1 and FB2 in baby food, 400 µg/kg in breakfast cereals, and 3700 µg/kg in animal feed. All samples were sent as blinded duplicates.Mean recoveries were calculated as 71 % for baby food, and 87 % for breakfast cereals. Based on results for the spiked and naturally contaminated samples the relative standard deviations for reproducibility (RSDR) in baby food were 31 % at a spiked level of 135 µg/kg, 44 % at a natural contamination level of 267 µg/kg, and 33 % at a natural contamination level of 501 µg/kg. For breakfast cereal these figures were 15 % at a spiked level of 400 µg/kg, and 33 % at a natural contamination level of 1034 µg/kg. The values for RSDr in those materials ranged from 5 to 29 % in baby food and 12 to 14 % in breakfast cereal.