Development and validation of the one-step purification method coupled to LC-MS/MS for simultaneous determination of four aflatoxins in fermented tea

Schematic description of the extraction, cleaning, and analytical protocol of four aflatoxins determination in fermented tea samples. 10–20%, 50%, and 100% represent different degrees of fermentation. [Display omitted] •A sensitive and accurate LC-MS/MS method for detecting aflatoxins in fermented tea was established.•One-step purification has substantially enhanced the easiness and universality of approaches.•MWCNTs-COOH was confirmed with the capability to clean-up complicated fermented tea matrices. Aflatoxin B1 is the potential chemical contaminant of most concern during the production and storage of fermented tea. In this work, a simple, fast, sensitive, accurate, and inexpensive method has been developed and validated for the simultaneous detection of four aflatoxins in fermented tea based on a modified sample pretreatment method and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Aflatoxins were extracted using acetonitrile and purified using mixed fillers (carboxyl multiwalled carbon nanotubes, hydrophilic-lipophilic balance, silica gel). Under optimum LC-MS conditions, the limits of quantification (LOQs) were 0.02–0.5 µg·kg−1. Recoveries from aflatoxins-fortified tea samples (1–12 µg·kg−1) were in the range of 78.94–105.23% with relative standard deviations (RSDs) less than 18.20%. The proposed method was applied successfully to determine aflatoxin levels in fermented tea samples.