Abstract:

A method was developed for simultaneous determination of four mycotoxins (aletrnariol monomethyl ether,
tentoxin, alternariol, and citrinin) in citrus fruits using ultra-performance liquid chromatography-tandem mass spectrometry
combined with optimized QuEChERS. Samples were extracted with acetonitrile, salted out with anhydrous MgSO4 and
NaCl, cleaned up with C18 and then analyzed using UPLC-MS-MS in multiple reaction monitoring (MRM) mode with
electrospray ionization. The separation of the target mycotoxins was performed on an ACQUITY UPLC BEH C18 liquid
chromatography column through gradient elution using a mobile phase consisting of acetonitrile and 0.1% formic acid
aqueous solution and the matrix-matched external standard calibration was used for quantitation. This method had a good
linearity in the concentration range of 5.0–200 μg/L with correlation coefficients (R2) more than 0.992 7, and the limit of
detection of the established method was in the range of 0.2–0.7 μg/kg. The average recoveries of the four mycotoxins in
different matrixes (citrus pulp, peel and whole fruit) at three spiked levels ranged from 78.0% to 103.3%, with relative
standard deviations (RSDs) of 2.6%–10.6%. This method is simple, quick, accurate, sensitive, and suitable for the quick
confirmation and quantitative determination of the four mycotoxins in citrus fruits.

Key words: ultra-high liquid chromatography-electrospray ionization tandem mass spectrometry, QuEChERS, citrus, mycotoxins