Simultaneous Determination Of13Mycotoxins In Grain By High Performance Liquid Chromatography-Quadrupole-Time Of Flight Mass Spectrometry

Mycotoxins are toxic secondary metabolites produced under a suitable climatic conditions by filamentous fungi that grow on grain commodities. They have been widely recognized as the main undesirable substances in grain and a potential threat to human health, food security and economic development. Around400different chemical structures have been confirmed so far which are classified as more important food-borne risk factors than synthetic contaminants, plant toxins, food additives or pesticide residue. There are more than ten mycotoxins that have big hazard to human body health, and grains contaminanted by multi-mycotoxins are universal. In order to fully understand the pollution condition of mycotoxin in grain, and provide the reliable data for food quality safety supervision and risk assessment of mycotoxin intaked in, we need to develop a simultaneous determination technology platform of multi-mycotoxin.A method appling solid phase extraction technology in combination with liquid chromatography-quadrupole time-of-flight mass spectrometry, using one step extraction and two step purification, was developed for the simultaneous determination of13mycotoxins(trichothecenes, aflatoxins, fumonisins, ochratoxinA and zearalenone) in wheat and maize. This method could achieve quick screening and conclusive evidence of analysis. After samples were extracted by acetonitrile-water-acetic acid (84:15:1,V/V), the mixture was filtered, and the filtrates were divided into two parts which were further cleaned up by the Mycosep226multifuctional cartridge and the strong anion exchange cartridge, respectively. Finally, the two parts of the purified extracts were combined and analysed by LC-Q TOF MS. The accurate mass database of13mycotoxins established in this study would be able to realize rapid automated screening, identification and confirmation of the mass spectrometric results. Under the mode of positive electrospray ionization using Q TOF MS, mycotoxins in the extracts were identified by the retention time and the mass accuracy of [M+H]+or [M+NH4]+, and the quantification of mycotoxins was carried out in exact mass chromatograms with a mass window width of10ppm. The results indicated that13mycotoxins had good linear relationships within their respective linear ranges and the accurate mass errors were lower than5ppm in wheat and maize samples. The limits of quantification ranged from1μg/kg to300μg/kg, and the average recoveries for the three spiked levels were ranged from70.2%～109.7%with the relative standard deviations of0.2%～14.5%. The established method were used to determinate mycotoxins in actual wheat and maize samples and the results were compared with the liquid chromatographic results. The simultaneous determination method of13kinds of important mycotoxins established in this study not only was able to realize rapid automated screening and confirmation of the mass spectrometric results, but also could provide reliable technical support for the comprehensive understanding the pollution condition of mycotoxin in grain.