Multitoxin extraction and detection of thricotecenes in cereals: an improved LC-MS/MS approach

Many multiresidual methods to evaluate natural occurrence of Fusarium toxins are already reported in scientific literature but a new rapid, reliable, cost-efficient and high sensitivity method for the simultaneous determination of several fusariotoxins is always welcome. Nivalenol, deoxynivalenol, fusarenon-X, 3-acetyldeoxynivalenol, diacetoxyscirpenol, HT-2 toxin, T-2 toxin, neosolaniol, zearalanone and zearalenone belong to the most common mycotoxins in food matrices grains, e.g wheat and maize. The proposed method is a multitoxin analytical method that combines high-performance liquid chromatography (HPLC), Atmospheric Pressure Chemical Ionization (APCI), triple quadrupole tandem mass spectrometry (LC-MS/MS) under the selected reaction monitoring (SRM) mode, and it is focused on the optimization of the sample preparation without the need for any clean-up. Three different methods for sample preparation and for the simultaneous extractions of the above mentioned fusariotoxins were tested: two of these were followed by a different clean-up step for comparison, while the extraction method proposed in this work, that uses an 84% (v/v) acetonitrile aqueous solution, sample homogenization and subsequent filtration, was validated without any further clean-up step. Calibration curves for all analytes are linear, except DAS, HT-2 and ZON, over the working range of 10-1000 µg/kg. The calibration curve of DAS was linear between 10-500 µg/kg, although the curves of HT-2 and ZON were linear in the range 10-250 µg/kg. Squared correlation coefficients (R2) were in the range 0.995-0.998 for the all point calibration curves. The lowest LODs were found for DON and ZAN with 0.5 µg/kg and 0.2 µg/kg, respectively, while the highest LODs were obtained for NIV, FUS-X and NEO with 3.3 µg/kg for each toxin.