Natural deoxynivalenol (DON) contamination of wheat samples grown in 1998 as determined by high-performance liquid chromatography.

A high-performance liquid chromatography--diode array detection (HPLC-DAD) method was developed for determining the deoxynivalenol (DON) content of wheat and other cereals. The samples were extracted with a mixture of acetonitrile and water (84 + 16). Part of the extract was evaporated and purified on Florisil and activated charcoal columns. HPLC separation was performed on a C18 column, using acetonitrile-water (8 + 92) as eluent. Diode array detection (DAD) was performed at 218 and 236 nm, by determination of the UV spectrum. Quantitative analysis was carried out by the external standard method, using the UV spectrum obtained by DAD for confirmation. The recovery rate of DON was 75 +/- 3.1% and the detection limit was 0.05 mg/kg DON. Using this method, the DON content of 99 feeding wheat samples grown in the northeastern part of Hungary in 1998 was determined. Eighty-eight percent of the samples originating from three counties contained 0.94 mg/kg DON on the average. The highest individual value was 4.3 mg/kg. DON contamination of wheat was of higher prevalence (100%) and severity (0.27-4.3 mg/kg) in the southeastern county of Békés than in Szabolcs county located in the northeastern part of Hungary (ratio of positive samples: 82%; DON concentration: 0.05-1.3 mg/kg). The higher than usual DON contamination of feeding wheat can be explained by the rainy summer weather. DON contamination of feeding wheat poses a major risk to the production and animal health status of pig herds.