Determination of type A trichothecenes by high-performance liquid chromatography with coumarin-3-carbonyl chloride derivatisation and fluorescence detection.

A method for the analysis of type A trichothecenes T-2 toxin, HT-2 toxin, neosolaniol and diacetoxyscirpenol by high-performance liquid chromatography with fluorescence detection using coumarin-3-carbonyl chloride has been developed. Different parameters concerning the analytical procedure such as stability of both the reagent and derivatised analytes, time and temperature of the derivatisation reaction, were studied and optimised. Three different clean-up procedures (solid-phase extraction with silica gel or C-18 cartridges, and liquid-liquid partition between toluene and dihydrogen phosphate buffer) were tested in order to remove the excess reagent peaks. The last procedure gave the best results when the buffer pH was 3-5.5, and is therefore recommended. Separations were performed on a stainless steel LiChrospher 100 C-18 reversed-phase column with pre-column of the same phase. The mobile phase was acetonitrile/water (65:35, v/v) containing 0.75% acetic acid at a flow-rate of 1.0 ml/min. The proposed method provides good separation between the four trichothecenes and good reproducibility (RSD of calibration standards <5%). The limits of detection of the studied trichothecenes at a signal-to-noise ratio of 3:1, with an injection volume of 20 microl were 10 ng/g sample for T-2 toxin and about 15 ng/g sample for the remaining mycotoxins. The calibration curve was linear between 10 and 2000 ng for the four trichothecenes assayed. The method was applied to the analysis of these mycotoxins in fungal cultures (corn and rice) of Fusarium sporotrichioides, and is also perfectly suitable for the quantification of type A trichothecenes in contaminated cereals.