Abstract:A method was established for the determination of ten mycotoxins (aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1 (AFG1), aflatoxin G2 (AFG2), deoxynivalenol (DON), 3-acetyldeoxynivalenol (3-AcDON), zearalenone (ZEN), T-2 mycotoxin (T-2), HT-2 toxin (HT-2), and ochratoxin A (OTA)) in fermented dark tea (Pu'er tea, Hunan dark tea, Guangxi Liupu tea, and Hubei old green tea) using (QuEChERS) ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with acetonitrile-water (84:16, V/V), and the extracted solutions were purified using the QuEChERS approach. The mycotoxins were then separated on an Agilent Zorbax Rrhd SB-C18 column (2.1 mm×100 mm, 1.8 μm) using (0.1% formic acid-5 mM ammonium acetate-water)/methanol as the mobile phase and detected by MS/MS under multiple reaction monitoring (MRM) mode. The mass spectrometry measurement was conducted using positive (ESI+) and negative (ESI-) electrospray ionization with an external standard. The results showed that ten mycotoxins had a good linear relationship within their own linear response ranges, with correlation coefficients (r) all >0.9995. The limits of quantitation (LOQ) (S/N≥10) were 0.1~1.0 μg/kg, and the average recoveries at three spike levels of ten mycotoxins ranged from 61.9% to 120.3%, with a relative standard deviation (RSD, n=3) of 3.2%~16.1%. This newly developed method was successfully applied for the assessment of 61 commercial black tea samples, and mycotoxins were detected in several batches of samples. Based on these results, the developed method is reliable, simple, and accurate, and is suitable for the rapid analysis of multiple mycotoxin contaminants in fermented dark tea.
