Simultaneous Determination of Type A, B and D Trichothecenes in Maize Products by HPLC-ESI-MS/MS

Trichothecenes, the largest group of Fusarium mycotoxins, constitute the main natural contaminants of cereals in the temperate regions of America, Asia and Europe. They act at biochemical and cellular level, exhibiting acute, chronic, mutagen and teratogen toxicity in humans and animals. Trichothecenes are polycyclic sesquiterpenoids characterized by a C9-C10 double bond, by a variable number of hydroxyl and acetoxy groups and by a C12-C13 epoxide ring. Depending on their functional groups, they have been classified in four groups, named A, B, C and D1,2. Within the European Union, an opinion on the Fusarium toxins was expressed by the Scientific Committee for Food since 19993,4 and by means of the Commission Regulation 2005/856/CE5, modifying previous one 2001/466/CE, were established new Daily Acceptable Intake (ADI) for the most dangerous Fusarium toxins, but none maximum residue limit (MRL) for the trichothecenes except the most frequently occurring deoxynivalenol; before 1st July 2007 a tolerance level will be fixed also for T-2 and HT-2. A new method of analysis, based on liquid chromatography-tandem mass spectrometry, for the simultaneous determination of type-A (T-2 toxin, HT-2 toxin, diacetoxy-scirpenol, monoacetoxy-scirpenol, neosolaniol), type-B (nivalenol, deoxynivalenol, 3-acetyl-deoxynivalenol, 15-acetyl-deoxynivalenol, fusarenon-X) and type-D trichothecenes (roridine and verrucarine) has been developed and validated on maize flour and oil. Analytes were separated on a analytical C18 column using acetonitrile as organic solvent and were detected by means of electrospray interface adding ammonium acetate (0.07 mM) to both mobile phases and selecting [M+NH4]+ as pseudomolecular ion; in order to confirm toxins identity, two multi-reaction-monitoring transitions were selected for each analyte. The analytical method was validated according to the European Commission Decision 2002/657/EC on both food matrices. The trichothecenes were extracted by means of matrix solid phase dispersion from maize flour with recoveries ≥ 79% and by means of liquid-liquid extraction from maize oil with recoveries ≥ 72%. The limits of detection were ≤ 17 ppb for maize flour, and ≤ 57 ppb for maize oil; according to indications of Regulation 856/2005/EC, the decision limit (CCalfa) and detection capability (CCbeta) were estimated only for deoxynivalenol. The developed method was applied to detect the occurrence of trichothecenes residues in some commercial products; however positive samples did not exceed law level