Determination of trichothecenes in wheat by capillary gas chromatography with flame ionisation detection

Trichothecenes are mycotoxins produced by several fungal genera. The Fusari um species, mainly, can contaminate a wide range of cereals used for human and animal consumption. Trichothecenes are associated with various adverse health effects in animals and humans. Deoxynivalenol (DON) and nivalenol (N IV) are the trichothecenes most commonly found worldwide, although 3-acetyl deoxynivalenol, fusarenon X, T-2 toxin, HT-2 toxin, diacetoxyscirpenol (DAS ) and neosolaniol are also found. They are included in the present study. F or the determination of these trichothecenes in wheat, a method based on ca pillary gas chromatography (GC) with flame ionisation detection (FID) has b een developed and validated. The trichothecenes are extracted from the samp le matrix by acetonitrile/water (84/16, v/v). Two different Mycosep(R) clea n-up columns are used to purify the extract. The extract is evaporated to d ryness and the trichothecenes are derivatised to trimethylsilyl ethers at r oom temperature. The residue is dissolved in iso-octane and washed with wat er. The final extract is analysed for trichothecenes by GC with FID. Quanti fication is based on the internal standard a-chloralose. The average recove ries for the trichothecenes range from 79% for NIV to 116% for DAS. The lim it of quantification is 75 mug/kg for each of the individual trichothecenes . The GC-FID method produced good results in an intercomparison study of tr ichothecene analysis within the European Union Standards, Measurements and Testing Programme. A survey was carried out in the Netherlands in 1999 to d etect the presence of trichothecenes in imported wheat. A temporary toleran ce limit of 500 mug/kg is in effect in the Netherlands for DON in cleaned w heat. Seven of the 22 wheat samples exceeded this limit; one exceeded the l imit by more than 100%. Thirteen of the 22 wheat samples exceeded a propose d DON tolerance limit of 120 mug/kg for cleaned wheat. Indeed, 12 samples e xceeded the limit by more than 100%. Besides DON, no trichothecenes were fo und in the wheat samples at levels above the limit of quantification. (C) 2 001 Elsevier Science Ltd. All rights reserved.