Simultaneous Analysis Mycotoxin Residues In Milk By UPLC-MS/MS Method And The Risk Analysis Research

In recent years, China’s dairy production stagnated, imports soared, consumers have no confidence in domestic milk because of the precarious situation and frequently incidents of milk quality and safety. After the2011aflatoxin Mi incident of milk, mycotoxin contamination in milk has evoked concern of consumers. Mycotoxins in milk, mainly coming from contaminated feed, has become one of the important risk factors because of common mycotoxin contaminations in feed ingredients. Therefore, studing mycotoxin detection technology and monitoring its risk can prevent mycotoxin contamination incidents effectively, and conducive to enhancing the quality and safety of milk. In this study, a sensitive and reliable method has been developed for the simultaneous determination of aflatoxin Mi (AFM1), ochratoxin A (OTA), zearalenone (ZON), and a-zearalenol (a-ZOL) in milk by ultra-performance liquid chromatography combined triple quadrupole tandem mass spectrometry (UPLC-MS/MS), and this method had been used to monitor mycotoxin contaminations of raw milk. The main contents are as follows:(1) In this study, a sensitive and reliable method has been developed for the simultaneous determination of four mycotoxins—aflatoxin Mi, ochratoxin A, zearalenone, and a-zearalenol—in milk by ultra-performance liquid chromatography combined with electrospray ionization triple quadrupole tandem mass spectrometry (UPLC-ESI-MS/MS). The mycotoxins extracted with acetonitrile were purified and concentrated from milk samples using Oasis HLB cartridge under optimized conditions. The mycotoxins were separated by UPLC BEH C18column and eluted with aqueous ammonia/methanol for ESI+and ESI-analysis in only-2min. The matrix effects were evaluated by the signal suppression-enhancement and corrected by external matrix-matched calibration for accurate quantification. The LOQ ranges of selected mycotoxins were0.003-0.015μg/kg. Meanwhile, high correlation coefficients (r2≥0.996) of all mycotoxins were obtained within their respective linear ranges (0.01-1.00μg/kg), and reasonable recoveries (87.0-109%) were also demonstrated at different spiked levels. These good results demonstrated that the proposed method was suitable for the simultaneous determination of selected mycotoxins in milk and could provide technical support for their routine analysis in mycotoxin study and monitoring.(2) To study mycotoxin contaminations of raw milk, mycotoxin contaminations (aflatoxin Mi, ochratoxin A, zearalenone and a-zearalenol) were determined by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). One hundred and seventy eight raw milk samples were collected from eight main milk production districts. The results of178raw milk samples collected from eight main milk production districts showed that:the contents of mycotoxins in all samples were less than500ng/kg, but all mycotoxins were detected. The detection rate, average and maximum concentration of AFM1、OTA、ZON and a-ZOL were84.3%,14.7and96ng/kg;37.1%,20.4and199ng/kg;87.6%,22.1and112ng/kg;74.2%,37.1and137ng/kg, respectively. Only2%of the sample was not detected mycotoxins, and94%of the samples contaminated muti-mycotoxin. There was100%detection rate of aflatoxin Mi in Tianjin and Shandong Province, zearalenone in Shanxi, Tianjin and Shandong, a-zearalanol in Shandong were detected100%, but no significant difference of mycotoxin detection rates were found in different provinces (P>0.05). Average and maximum concentration of mycotoxins in raw milk were at trace levels and well below500ng/kg. Therefore, concerning mycotoxins, our country’s milk was quality and safety, but high detection rates and widespread multi-mycotoxin contaminations indicated that the risk of mycotoxin contaminations in milk should be paid heavy attention.