Multi-mycotoxin LC-MS/MS method validation and its application to fifty-four wheat flours in Hungary

In this study, fifty-four wheat flour and wheat-based products available on the Hungarian market were assessed for twelve mycotoxins. Prior to analysis, a multi-mycotoxin method using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS) was developed and validated for wheat and wheat-based products. A simple extraction with acetonitrile/water/formic acid (79/20/1 v/v%) was used for sample preparation. The limits of quantitation (LOQ) were between 0.02 and 161 μg kg^-1. Good linearity (r² > 0.995) was achieved for all mycotoxins investigated. Recoveries varied between 88 and 120% at three concentration levels. Based on the low relative matrix effect (RSD < 0.15%) of the different wheat flour samples, matrix-matched calibration was used, which also proved its suitability in proficiency testing (z-scores: -0.6 for DON; +1.5 for OTA; -0.5 for ZEA). DON was the predominant mycotoxin, which contaminated 84% of the investigated samples. Metabolised forms of DON were found in spelt, durum flour and some wheat-based products (D3G in 4 samples, 15Ac-DON in 7 samples). T-2 and HT-2 were the second most frequently detected mycotoxins. All investigated samples complied with current European/Hungarian legislation.