INTERLABORATORY COMPARISON STUDY FOR THE DETERMINATION OF THE FUSARIUM MYCOTOXINS DEOXYNIVALENOL IN WHEAT AND ZEARALENONE IN MAIZE USING DIFFERENT METHODS

Seventeen laboratories from six different countries, using their usual in-house methods, participated in an interlaboratory comparison test for the determination of the Fusarium mycotoxins deoxynivalenol (DON) in wheat and zearalenone (ZON) in maize. The toxins generally were ext racted from maize and wheat employing mixtures of water, acidified wat er with an organic solvent or even pure water (for DON). While partici pants who used enzyme linked immune sorbent assays (ELISA) for the det ermination of DON did not perform any clean-up? various techniques wer e applied for the purification of raw extracts (e.g. liquid/liquid ext raction, solid phase extraction (SPE), immune affinity chromatography (IAC)). For the final separation/quantification step either high perfo rmance liquid chromatography (HPLC) (mostly for ZON), gas chromatograp hy (GC) (for DON) or ELISA were employed by participants. The aim of t his study was to obtain information about the state of the art of myco toxin analysis in cereals and to support a knowledge and experience ex change between the participating laboratories in the field of mycotoxi n analysis. For each mycotoxin 5 different sample types were distribut ed, standard solutions (10.10 mu g/ml ZON in methanol, 10.09 mu g/ml D ON in ethyl acetate), blank materials, spiked samples (75.1 mu g/kg an d 378.3 mu g/kg ZON in maize, 126.2 mu g/kg and 2519 mu g/kg DON in wh eat) and naturally contaminated maize and wheat. Coefficients of varia tion (CV) between laboratory mean results (outliers excluded) ranged f rom 6.2 to 27.7% for ZON and from 18.9 to 30.0% for DON. Except for th e maize samples spiked at 75.1 mu g/kg ZON the overall means (outliers rejected) statistically could not be distinguished from the respectiv e target values. Average recoveries of the reported results ranged fro m 87.7 to 96.2% for ZON and from 94.2 to 108.5% for DON.