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 w heat and other cereals. The samples were extracted with a mixture of aceton itrile and water (84 + 16). Part of the extract was evaporated and purified on Florisil and activated charcoal columns. HPLC separation was performed on a C-18 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 m ethod, 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. Us ing this method, the DON content of 99 feeding wheat samples grown in the n ortheastern part of Hungary in 1998 was determined. Eighty-eight percent of the samples originating from three counties contained 0.94 mg/kg DON on th e 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 Bekes than in Szabolcs county located in the northe astern 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 c an be explained by the rainy summer weather. DON contamination of feeding w heat poses a major risk to the production and animal health status of pig h erds.