Analysis of zearalenone and α-zearalenol in animal feed using high-performance liquid chromatography

Different extraction and clean-up techniques used before HPLC analysis were compared in order to obtain a reliable method for the quantitative determination of zearalenone (ZEA) and alpha-zearalenol (alpha-ZOL) in animal feed. Immunoaffinity clean-up was compared to C 18 and Florisil column clean-up. Extracted samples were analysed by reversed-phase HPLC with fluorescence detection (lambda(ex) = 274 nm, lambda(em) = 440 mm). A mobile phase of acetonitrile: water (50:50 (v/v)) and a flow-rate of 1.0 ml min(-1) resulted in a good separation between ZEA and alpha-ZOL. Using immunoaffinity clean-up the linear range was between 25 and 600 mug kg(-1) forZEA and alpha-ZOL in maize. Intra-laboratory coefficients of variation (CV) (under repeatability conditions) were 9.16% for ZEA and 2.18% for alpha-ZOL. Recoveries for spiked ZEA and alpha-ZOL samples ranged from 89 to 110% with CVs between 5.2 and 11.2% (under within-laboratory reproducibility conditions). Using C-18 and Florisil solid-phase clean-up, matrix interference was too high. Therefore, naturally contaminated animal feed samples were analysed using the developed HPLC method coupled to the immunoaffinity clean-up. (C) 2003 Elsevier Science B.V. All rights reserved.