Capillary gas-liquid chromatographic determination of vomitoxin in cereal grains

A gas-liquid chromatographic (GLC) method, using an electron capture detector, is described for determining vomitoxin in cereal grains at levels as low as 0.05 ppm. Samples are extracted with chloroform-ethanol and initially purified by using a Sep-Pak silica cartridge, followed by column chromatography using Sephadex LH-20. Additional purification is achieved by using a disposable cyano cartridge. Heptafluorobutyrylimidazole (HFBI) is added to form esters of the analytes. The HFB esters of vomitoxin are separated on a 30 m X 0.25 mm fused silica column coated with SE-54 and measured with a 63Ni electron capture detector. Samples were confirmed by gas-liquid chromatography/mass spectrometry using electron impact ionization and single ion monitoring at the molecular ion mass of 884.05 and at 10 000 resolving power. The method has been applied to wheat, oats, barley, and corn. The limit of detection is 0.05 ppm vomitoxin. Average recoveries were 89.8% with a coefficient of variation of 4.0%.