HPLC determination of aflatoxin M1 in liquid milk and milk powder using solid phase extraction on OASIS HLB

A facile and inexpensive method using solid phase extraction (SPE) on OASIS HLB and HPLC with fluorescence detector (FLD) determination of aflatoxin M1 (AFM1) in liquid milk and milk powder was described. The detection limits of this method provided were 0.006 μg/kg for liquid milk and 0.026 μg/kg for milk powder. The recoveries obtained in all food matrices were between 85.4 and 96.9%, and the RSDs were between 0.8 and 3.6%. Furthermore, a total of 31 samples were detected using OASIS HLB and immunoaffinity column (IAC) as a comparison, both cleanup methods obtained consistent results. The level of AFM1 contamination found in 8 samples among the tested samples did not exceed the Chinese legal limit (0.5 μg/kg). This method was applied successfully to analyse AFM1 in liquid milk and milk powder without interference peaks.