A method for determining deoxynivalenol (DON) in wheat has been developed in conjunction with an assessment of contamination in Canada. The sample is extracted with methanol-water; the extract is treated with 30% aqueous ammonium sulfate solution and extracted with 4 portions of ethyl acetate. After further cleanup by column chromatography, the sample extract is derivatized with AT-heptafluorobutyrylimidazole, and the DON tris-heptafluorobutyrate is determined by gas-liquid chromatography with electron capture detection. Mass spectrometric single ion monitoring at m/z 884 is used for confirmation. Detection limits are ≤0.01 μg DON/g and recoveries from wheat, using the proposed method, averaged 72 and 80% in 2 different laboratories, with coefficients of variation of 10.2 and 10.0%, respectively. The method is also applicable to determining DON in barley and corn and T-2 toxin in wheat. Virtually 100% contamination by DON of the 1980 Ontario white winter wheat and Quebec red spring wheat crops was found, based on 72 analyses made in this laboratory, but western Canadian wheat contained little or no DON.
Methyl p-dimethylaminobenzenesulfonate rearranges in the solid state, as a malt, and in solution to a zwitterionic product, p-trimethylammoniumbenzenesulfonate. By a combination of kinetic and field desorption mass spectrometric techniques, we have found that the reaction is intermolecular and that it proceeds at a considerably faster rate in the crystal than it does either in the melt or in solution. The structure of the starting sulfonate has been solved by single crystal x-ray diffraction, and this study revealed that the molecules in the crystal are nearly ideally oriented for reaction in the solid state. Powder diffraction studies have shown that due to the constraints of the starting crystal lattice, the product is initially formed in a metastable crystalline form which slowly reverts to its thermodynamically most stable crystalline modification.
Autoimmune subepidermal blistering diseases in dogs were all classified as bullous pemphigoid until 1998. Since then, refinements in reagents and immunological techniques have allowed diseases which are histologically similar but which have a different molecular pathogenesis to be described. This report describes the first case of one such disease, epidermolysis bullosa acquisita, to be documented in the UK. The dog presented with a severe blistering and ulcerative disease affecting the oral cavity, pinnae and distal limbs. The diagnosis was confirmed by histopathology and direct and indirect immunofluorescent demonstration of immunoglobulin G reactivity to basement membrane antigens. Treatment with glucocorticoids, azathioprine, colchicine and an intravenous infusion of immunoglobulins resulted in complete resolution. The drugs were discontinued 12 months after the start of treatment and the dog remained in remission.
Four batches of Egyptian bread were prepared using flour spiked with deoxynivalenol (DON) at a level of 2 μg/g in one batch and naturally contaminated flour (3.3 μg/g of DON) in the remainder. These breads, as well as the corresponding flour and fermented dough, were analyzed to follow the fate of DON during processing. Gas liquid chromatography (GLC) with electron capture (EC) detection was used for determination of DON and the results from two experiments were confirmed by GLC-mass spectrometric single ion monitoring [MS (SIM)]. Neither preparation of fermented dough nor the baking process (350°C for 2 min) affected the amount of DON in either spiked flour or naturally contaminated flour.
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