Development of isotope dilution-ultrahigh-performance liquid chromatography-tandem mass spectrometry for the accurate determination of aflatoxins in grains

Abstract

A method for the accurate determination of aflatoxin B1, B2, G1, and G2 in grains was established using isotope dilution-ultrahigh-performance liquid chromatography-tandem mass spectrometry (ID-UHPLCMS/MS). 13C- labeled aflatoxins (AFs) were used as internal standards. AFs were extracted with a mixture of methanol/water (60/40; v/v) and purified using an immunoaffinity column (IAC) for adequate elimination of matrix interferences. The method showed excellent analytical performance over the studied range (0.5–4 µg/kg). The limits of detection (0.002–0.005 µg/kg) and quantification (0.007–0.011 µg/kg) were substantially lower than the maximum level fixed by the European Union for grain cereals. The accuracy values ranged from 97 % to 103 % for all AFs, with intraday and interday precisions ranging from 1.8 % to 3.0 % and 0.3–3.8 % relative standard deviation (RSD), respectively. The measurement uncertainty was less than 4.20 %. The developed method shows high-order metrological quality with superior performance over the existing analytical methods. The practical applicability of the method was demonstrated by the measurement of AFs in different grain samples.