Rapid Determination of Five Alternaria Mycotoxins in Citrus by Ultra-high Performance Liquid Chromatography-Tandem Mass Spectrometry

A novel method was developed for the rapid determination of five alternaria mycotoxins, alternariol, alternariol monomethyl ether, altenuene, tentoxin and tenuazonic acid, in citrus using ultra-high performance liquid chromatography. tandem mass spectrometry. The sample was prepared using the modified QuEChERS (quick, easy, cheap, effective, rigged, and safe) method to complete the extraction and clean-up steps in one procedure. In this QuEChERS method, sample was extracted with acetonitrile (1.5% formic acid), then salted out with anhydrous MgSO4 and NaCl, separated on an ACQUITY UPLC BEH C-18 with gradient elution by using acetonitrile and 0.1% formic acid aqueous as eluant, and detected by UPLC-MS/MS under negative (ESI+) electrospray ionization and MRM models. Under these conditions, five alternaria mycotoxins made a good linearity in the concentration range of 2.0-100 mu g/L with R-2 > 0.9922, and the limits of detection of the instrument were in the range of 0.11-0.91 mu g/kg. Three spiked levels of five altenaria mycotoxins at 5, 20 and 100 mu g/kg were investigated, and the recoveries ranged from 71% to 112% with the relative standard deviations (RSDs) varying from 1.1% to 9.9%, which met the requirement of mycotoxins determination.