Abstract: A liquid chromatography-tandem mass spectrometry (LC-MS/MS) method was established for simultaneous determination of 4 aflatoxins in peanut oil including aflatoxins B1, B2, G1 and G2. The sample preparation was achieved by sequential extraction with aqueous methanol solution and chloroform. The analytes were separated on a C18 column using a mobile phase composed of acetonitrile and 0.1% aqueous formic acid solution and detected using electrospray ionisation (ESI)-MS/MS in positive ion mode with multiple reaction monitoring (MRM). The linear range of aflatoxins determination was from 0.0 to 20.0μg/kg. The recovery rates for four aflatoxins were from 70.8% to 108.0% at 1.0μg/kg and from 82.4% to 104.5% at 10.0 and 20.0μg/kg, and the relative standard deviations from 5.7% to 9.7%. The developed method proved highly selective and sensitive in determining 19 commercial peanut oil samples, thus being suitable for qualitative and quantitative analysis of four aflatoxins in peanut oil.

Key words: liquid chromatography-tandem mass spectrometry (LC-MS/MS), aflatoxins, peanut oil, multi-reaction monitor (MRM)