Structure elucidation and toxicity analyses of the degradation products of aflatoxin B1 by aqueous ozone

Earlier researches showed that aflatoxin B1 (AFB1) can be effectively degraded using ozonation in the aqueous systems. However, the degradation products have not been identified until today. In this article, the degradation products of AFB1 were analyzed using ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometers (UPLC Q-TOF MS). Under our experimental conditions, six key degradation product structures and possible paths for generating fragment ions were proposed. The proposals were based on the low mass error, high match rate in degradation product speculation, and possible molecular formulas that could be obtained using UPLC Q-TOF MS. UPLC revealed the existence of degradation products, whereas Q-TOF MS exposed the structures of the fragment ions for AFB1 and its degradation products. Due to the conjugate addition reaction on the double bond of the terminal furan ring for AFB1, the toxicity of the degradation products was significantly decreased compared with that of AFB1 through the toxicity analysis of the degradation products according to the structure–activity relationship. The results showed that aqueous ozone treatment was an effective method for degrading AFB1.