Abstract: An ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed for the simultaneous determination of 16 mycotoxins from different types of aged tea. The sample was extracted with formic acid-acetonitrile (10:90, V/V), added with a blend of QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction salts, shaken and centrifuged; the extract was cleaned up by passing through an OASIS PRIME HLB cartridge and a dispersive solid-phase extraction (dSPE) purification tube, separated on an ACQUITY UPLC HSS T3 C18 column, detected using an electrospray ionization source in the positive ion multiple reaction monitoring (MRM) mode, and quantified using tea matrix matching standard solution. The 16 mycotoxins showed a good linear relationship within their respective concentration ranges with correlation coefficients > 0.999. The average recoveries from tea matrix spiked at three different levels ranged between 63.4% and 109.7%, with relative standard deviations (RSDs) between 1.7% and 11.3%. The method limits of detection (LODs) ranged from 0.03 to 7.00 μg/kg. Among 121 aged tea samples selected for analysis, aflatoxin B1 was detected from one oolong tea sample at a concentration of 34.0 μg/kg, and ochratoxin A was also detected from one black tea sample at a concentration of 1.6 μg/kg. The method proved to be stable, accurate, sensitive and fast, and could meet the requirements for the analysis of multiple toxic residues in a variety of tea samples.

Key words: ultra-high performance liquid chromatography-tandem mass spectrometry; aged tea; mycotoxins