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.