Multi-mycotoxins analysis in raw milk by ultra high performance liquid chromatography coupled to quadrupole orbitrap mass spectrometry

This paper presents the development and application of a sensitive and specific method for the analysis of multi-mycotoxins in raw milk using ultrahigh performance liquid chromatography quadrupole orbitrap mass spectrometry (UHPLC/Q-Orbitrap). Mycotoxins (a total of 14) included in this study were aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, aflatoxin M1, aflatoxin M2, ochratoxin A, ochratoxin B, zearalenone, zearalanone, α-zeralanol, β-zeralanol, α-zeralenol, and β-zeralenol. Mycotoxins in milk were extracted and purified with a multi-mycotoxins AOZ immunoaffinity column in a single run, which made the matrix effect be negligible. The deliberate addition of small amount of acetonitrile was found to be beneficial for the extraction of mycotoxins from the complex milk matrix, especially for zearalenone and its derivatives. The final reconstituted extracts were analyzed using ultra high performance liquid chromatography coupled to quadrupole orbitrap mass spectrometry (UHPLC Q-Orbitrap mass spectrometry). The extraction recoveries are in the range of 60–106%, with coefficient of variation <15%. The limits of detection for the analytes are in the range of 0.0003–0.008 μg/kg. Compared with a triple-quadrupole mass method in MRM mode, the Q-orbitrap analyzer provides accurate masses of both the precursor and product ions, thus offers a higher level of confidence in analyte identification without the sacrifice of analytical performance. The method was successfully applied to investigate the occurrence of the 14 mycotoxins in a total of two hundred and fifty raw milk samples collected from 5 different provinces of China.