Development of a microwave-assisted-extraction-based method for the determination of aflatoxins B_1, G_1, B_2, and G_2 in grains and grain products

摘要

This article describes the use of microwave-assisted extraction (MAE) as a pretreatment technique for the determination of aflatoxins B_1, G _1, B_2, and G_2 in grains and grain products. The optimal operation parameters, including extraction solvent, temperature, and time, were identified to be acetonitrile as the extraction solvent at 80 C with 15 min of MAE. The extracts were cleaned up using solid-phase extraction followed by derivatization with trifluoroacetic acid and were determined by liquid chromatography-fluorescence detection. A Sep-Pak cartridge was chosen over Oasis HLB and Bond Elut cartridges. By the use of aflatoxin M_1 as an internal standard, relative recoveries of the aflatoxins ranged from 90.7 to 105.7 % for corn and from 88.1 to 103.4 % for wheat, with relative standard deviations between 2.5 and 8.7 %. A total of 36 samples from local markets were analyzed, and aflatoxin B_1 was found to be the predominant toxin, with concentrations ranging from 0.42 to 3.41 μg/kg. [Figure not available: see fulltext.]