Abstract: Two different analytical methods for determining aflatoxins in peanut, corn and rice were compared in this paper. Samples were extracted by 70% methanol supplemented with 4 g/mL NaCl and cleaned up by immunoaffinity columns. Half part of the eluent was derivated with hexane and trifluoroacetic acid, and detected by liquid chromatography with fluorescence detection (FLD), the rest part of the eluent was detected by liquid chromatography-electrospray ionization tandem linear ion trap mass spectrometer (LC-ESI-LTQ). Limits of detection (LOD) of AFB1, AFB2, AFG1 and AFG2 determined by LC-FLD were in the range of 0.5－1.5μg/kg, the correlation coefficients were in the range of 0.9979－0.9999, and the recovery rates of spiked samples were in the range of 50.29%－126.54%; LODs of AFB1, AFB2, AFG1 and AFG2 determined by LC-ESI-LTQ were in the range of 0.1－0.2μg/kg, the correlation coefficients were in the range of 0.9993－0.9998, and the recovery rates of spiked samples were in the range of 50.38%－121.27%. All results showed that liquid chromatography-electrospray ionization tandem linear ion trap mass spectrometric method was more selective and sensitive for the analysis and confirmation of aflatoxins in peanut, corn and rice than LC-FLD.

Key words: aflatoxin, liquid chromatography, liquid chromatography-electrospray ionization tandem linear ion trap mass spectrometer (LC-ESI-LTQ), method comparison