Characterization of trichothecenes by ammonia chemical ionization and tandem mass spectrometry

Observation of T-2 toxin and HT-2 toxin glucosides from Fusarium sporotrichioides by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS)

The trichothecenes produced by solid and liquid cultures of Fusarium sporotrichioides were evaluated with high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Along with the expected T-2 toxin HT-2 toxin and neosolaniol, two additional compounds were detected, which had ions 162 m/z higher than those in the mass spectra of T-2 toxin or HT-2 toxin. Fragmentation behavior of these two compounds was similar to that of T-2 toxin and HT-2 toxin. Based on LC-MS/MS behavior, it is proposed that the two compounds are T-2 toxin 3-O-glucoside and HT-2 toxin 3-O-glucoside. Production of the two glucosides was measured in kernels from wheat and oat inoculated with F. sporotrichiodes, as well as in cultures grown in liquid media and on cracked corn or rice. Production of glucosides in wheat and oats suggest that they may also be present in naturally contaminated cereals.

Identification of trichothecenes by thermospray, plasmaspray and dynamic fast-atom bombardment liquid chromatography-mass spectrometry

Thermospray, plasmaspray and dynamic fast-atom bombardment liquid chromatography-mass spectrometry are compared for the identification of six trichothecenes. Thermospray spectra of the trichothecenes exhibit only a very abundant ammonium adduct ion. Plasmaspray, which provides a more energetic ionization process than thermospray, produces some fragment ions in addition to an abundant ammonium adduct ion. The spectra obtained by dynamic fast-atom bombardment exhibit a protonated molecule, a glycerol adduct ion and numerous fragment ions formed by the losses of functional groups as neutrals in various combinations. Thermospray and plasmaspray are suitable only for monitoring of the trichothecenes, whereas dynamic fast-atom bombardment is suitable for monitoring and for structure characterization.

Use of M-series retention index standards in the identification of trichothecenes by electron impact mass spectrometry

A method for the reliable identification of a series of trichothecenes as their trifluoroacetate esters in porridge flake samples is described. The esters were separated by gas chromatography and identified from their retention times relative to n-alkyl-bis(trifluoromethyl)phosphine sulphide (M-series) retention index standards and their electron impact mass spectra. The relative retention times offer an independent identification method by which the reliability of the identification can be improved. The mass spectra and the relative retention times were obtained from the same gas chromatographic-mass spectrometric run. Detection limits were of the order to 0.005-0.05 mg/kg. All the flake samples including oats (ten of fourteen samples studied) contained deoxynivalenol (0.01-0.2 mg/kg) and one oat flake sample contained HT-2 toxin (0.008 mg/kg). The other trichothecenes monitored were not found.

Characterization of trichothecenes by tandem mass spectrometry using reactive collisions with ammonia

The use of low-energy (7 eV Elab) reactive collisions with ammonia provides a highly specific method for the characterization of trichothecenes since the collisions between the protonated molecule and ammonia not only produce ions formed by collisionally activated dissociation but ammonium adduct ions and ions formed by substitution reactions. The good detection limits (20-300 pg) and good quantitative reproducibility (relative standard deviations are 5-10%) mean that the use of reactive collisions with ammonia is also very suitable for monitoring and quantitative analyses.