Determination of Deoxynivalenol and Its Derivatives in Cereals and Its Products by Ultra-High Performance Liquid Chromatography- Tandem Mass Spectrometry with Modified Pass- Through Solid Phase Extraction Column

A modified pass-through solid phase extraction column was developed and designed for the pretreatment of deoxynivalenol and its 4 derivatives in cereals and its products. The solid sample (2.00 g) or liquid sample (5.00 g) was taken, and 400 μL of 1.0 mg·L^-1 internal standard mixed solution was added. The mixture was shaken, mixed well, and settled for 30 min. Then 20.0 mL of 84% (volume fraction) acetonitrile solution was added into the solid sample or 15.0 mL of acetonitrile was added into the liquid sample, and the mixed solution was swirled for 20 min and centrifuged for 5 min. About 8 mL of the supernatant obtained was treated with the modified pass-through solid phase extraction column (a mixture composed of 160 mg of C₁₈, 300 mg of graphitized carbon black, 100 mg of aminopropyl purifier (NH₂) and 300 mg of diatomite as filler), and 5.0 mL of filtrate was taken and blown to dryness by nitrogen at 40 ℃. Then 1.0 mL of water was added into the residue, and the solution was treated by ultrasound for 30 s, swirled for 30 s, and filtrated by 0.22 μm microporous filter membrane. Deoxynivalenol and its 4 derivatives were determined by ultra-high performance liquid chromatography-tandem mass spectrometry, with internal standard method for quantification. As shown by the results, the sample solution was clear and transparent after treatment with the modified pass-through solid phase extraction column, and the matrix effect of the 5 targets was significantly reduced. The linear range of the standard curves of 5 targets was in the range of 10-2 000 μg·L^-1, and detection limit (3S/N) was 5.0 μg·kg^-1. Test for recovery was made on wheat flour, rice, corn, beer and liquor, giving results in the range of 74.6%-106%, and RSDs (n=6) of the determined values were not more than 9.1%. The proposed method was applied to analysis of 162 samples, and deoxynivalenol was detected in wheat flour, corn, rice and beer, but only 3-acetylated deoxynivalenol and nivalenol were detected among the 4 derivatives.