Establishment of an isotope dilution LC-MS/MS method revealing kinetics and distribution of co-occurring mycotoxins in rats

An isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) method with a fast sample preparation using homemade clean-up cartridges was developed for simultaneous determination of co-occurring mycotoxins exemplified with aflatoxin B1 (AFB1) and T-2 toxin (T-2) in representative biomatrices of rat plasma, heart, liver, kidney, spleen, lung and brain in a total run time of 7 min. The established approach using stable internal standards of [ ¹³C ₁₇]-AFB1 and [ ¹³C ₂₄]-T-2 was extensively validated by determining the specificity, linearity (R ² ≥ 0.9990), sensitivity (lower limit of quantitation at 0.05 ng mL ^-1), accuracy (70.9-107.7%), precision (RSD ≤ 14.2%) and stability (≥70.8%). Based on this methodological advance, the subsequent kinetics and tissue distribution after oral administration of 0.5 mg kg ^-1 b.w. of both AFB1 and T-2 in rats were thoroughly studied. As revealed, both AFB1 and T-2 were rapidly eliminated with the half-life time (t _1/2) in plasma of 8.44 ± 4.02 h and 8.12 ± 4.05 h, respectively. Moreover, AFB1 accumulated in all organs where the highest concentration was observed in liver (1.34 μg kg ^-1), followed by kidney (0.76 μg kg ^-1). Notably, only low levels of T-2 were observed in spleen (0.70 μg kg ^-1) and in liver (0.15 μg kg ^-1). The achieved data as supporting evidence would substantially promote the practical application of the proposed LC-MS/MS method for in vivo toxicokinetics and toxicity studies of co-occurring mycotoxins imitating natural incidence in rat system.