Abstract: A rapid method was established for detecting 14 mycotoxins (aflatoxin B1, aflatoxin B2, aflatoxin G1, aflatoxin G2, aflatoxin M1, ochratoxin A, citrinin, T-2 toxin, sterigmatocystin, fumonisin B1, fumonisin B2, zearalenone, deoxynivalenol, and penicillic acid) in liquid milk by solid-phase extraction coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Samples were defatted and extracted with 0.1% formic acid acetonitrile and the extract was cleaned up with Oasis PRiME HLB solid-phase extraction column. The analytes were separated on HSS T3 column (2.1 mm × 100 mm, 1.8 μm) with a mobile phase composed of 0.1% formic acid and acetonitrile using gradient elution. Detection was carried out by tandem mass spectrometry using positive ionization in the multiple-reaction monitoring (MRM) mode. An external standard method was applied for quantification. Results showed that the limits of quantitation (LOQs) of 14 mycotoxins in matrices were between 0.5 and 5 μg/kg. Average recoveries at 3 different spiked levels were 67.7%–112.7% with relative standard deviation (RSD) of 0.43%–7.28%. With the advantages of rapidity, high purification efficiency, low matrix interference and accurate and reliable results, the method is useful for the analysis of mycotoxins in liquid milk.

Key words: liquid milk, solid-phase extraction column, ultra-performance liquid chromatography-tandem mass spectrometry, mycotoxins, rapid detection