Study On The Determination Of Aflatoxins In Food And Degradation Products By LC-MS

The contamination of mycotoxins is one of the most important element which effects the food safety. All of the world, a quarter of grains are contaminated with mycotoxins each year, which always causes human diseases and much damage to the crops, great economic losses. The major and the most poisonous is aflatoxin which has strong acute and chronic poison. If humans or animals eat the food and feed that contains aflatoxins, they could be induced to acute poisoning and liver cancer and so on in the long term.In recent years, the supervision and management on food safety has been enhanced gradually in our country. Detection and degradation of mycotoxins has become a hot topic in the academic field. In this paper, some grains and nuts are the analytical objects and we research the determination of aflatoxin B1, B2, G1 and G2, together with the law and the safety of the degradation of AFB1 in standard solution.A liquid chromatography-mass spectrometry method has been developed for the simultaneous determination of four aflatoxins residues in food. The samples were extracted with acetonitrile-water, oscillated and filtered, and then cleaned up by multifunctional clean coloum. The residues were determined by rapid high performance liquid chromatography tandem mass spectrometry and quantified by external standard method. The detection limits of aflatoxin B1, B2, G1 and G2 are respectively 0.026μg/kg,0.046μg/kg,0.031μg/kg and 0.043μg/kg. The linear ranges of aflatoxin B1 and G1 are 0.05μg/kg～10μg/kg, which of B2 and G2 are 0.1μg/kg～10μg/kg. The average recoveries in blank sample are 76.2%～108.0%, and the RSD are 2.2%～11.0%. The high performance liquid chromatographic method in GB/T5009.23-2006 has been contrasted with LC-MS method, the data proves that new method is more rapid and precise than traditional methods.Aflatoxin B1 in standard solution were degraded by NaOH, NaHSO3 and H2O2, the degradation products were detected by quadrupole time of flight mass spectrometry with high resolution ratio, and the degradation rate was detected by LC-MS method. The degradation product are m/z226.9533 (C12H11O2K), 284.9018(C16H13O5) and 240.9184(C14H9O4) in positive mode, and there is no degradation product in negative mode. The Mass Professional Profile software confirm that different degradation condition could produce different degradation products.