Accurate determination of aflatoxins in coffee by isotope dilution–ultrahigh-performance liquid chromatography–tandem mass spectrometry

초록

An analytical method using isotope dilution–ultrahigh-performance liquid chromatography–tandem mass spectrometry (ID–UHPLC–MS/MS) was developed to accurately determine aflatoxins (AFs, namely B1, B2, G1, and G2) in raw coffee bean, roasted coffee bean, and instant coffee. Uniformly labeled 13C-analogs of AFs were employed as internal standards. Initially, a water/methanol mixture of 20/80 (v/v) was used as the extraction solvent due to its high recovery rates for all AFs. However, the sample extract after undergoing clean-up using immunoaffinity columns exhibited substantial matrix interferences, leading to a bias in isotope ratio measurement. Consequently, a water/methanol mixture of 50/50 (v/v) was chosen to facilitate accurate isotope ratio measurement while effectively eliminating matrix interferences. The developed method displayed exceptional accuracy (97 %–103 %) for all AFs within the concentration of 0.5–4 µg/kg with interday and intraday precision of < 6 %. Furthermore, the measurement uncertainty remained below 5 % at a 95 % confidence level. Hence, the newly developed method shows high-order metrological quality, surpassing the performance of previously reported methodologies. © 2025 Elsevier Inc.

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