Establishment of appropriate conditions for the efficient determination of multiple mycotoxins in tea samples and assessment of their drinking risks

Conditions were determined for rapid, convenient, and efficient determination of 16 common mycotoxins in tea samples. Mycotoxins in tea leaves and tea infusion samples were extracted using solid-liquid extraction/liquid-liquid extraction combined with ultrasonic-assisted extraction. The extraction solvent was 2-butanone/ethyl acetate (9/1 v/v) with 0.1 % formic acid. The established conditions enabled the analysis of these mycotoxins by ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) in 5.5 min. In addition, HPLC with a temperature-controlled fluorescence detector was able to simultaneously determine 8 mycotoxins with fluorescent properties in 10 min without derivatization. Aflatoxin M1 (2.15 and 3.01 μg/kg), fumonisin B2 (198.89 μg/kg), and zearalenone (87.54 μg/kg) could be detected in commercially available pu-erh tea, green tea, and black tea products, and their total transfer rates from the products to brewed tea infusions were 64.08–65.13 %, 90.59 %, and 25.99 %, respectively. The risks of drinking mycotoxins from these tea infusions mostly showed low levels of concern.