Pressurized liquid extraction followed by liquid chromatography–mass spectrometry for determination of zearalenone in cereal flours

A method for determination of zearalenone in cereal flour has been developed applying pressurized liquid extraction (PLE) using methanol/acetonitrile (50:50 v/v) as the extraction solvent. The extracted samples were analyzed with liquid chromatography coupled to mass spectrometry (LC–MS) with an electro spray ionisation interface (ESI). The method was validated as a quantitative confirmatory method according to the Eu Commission Decision 2002/657/EC. Recoveries of the extraction step data were satisfactory with values higher then 70%. Quantification limits (LOQ) were 5 μg/kg for ESI (+) and 1 μg/kg for ESI (−). Twenty one flour samples produced in different countries were extracted and analyzed by LC–MS (ESI) negative ionisation followed by LC–MS (ESI) positive ionisation for confirmative purposes, quantification was based on matrix-matched standard curves to compensate disturbing matrix effect. Only one sample was confirmed containing zearalenone below levels regulated by European Commission.