RP-HPLC Determination of Aflatoxin M1 in Milk and Its Products

RP-HPLC was applied to the determinations of aflatoxin M1 (AFM1) in milk and its products.The sample was extracted with chloroform,and purified by passing through silica gel solid phase extraction column,and AFM1 was eluted from the SPE column with a mixed solution of chloroform and acetone (1+1).The eluate was separated by gradient elution with acetonitrile solution of different concentration from ZORBAX SB C18 column,and their contents determined by fluorescence detector.Linear relationship between values of peak area and mass concentration of AFM1 was obtained in the range of 1.0-25 μg·L-1,with detection limit (3S/N) 0.05 μg·kg-1.The proposed method was used in the analysis of milk and milk powder for their contents of AFM1 and values of recovery found by standard addition method were in the range of 76.0%-80.0% and 76.7%-90.8% respectively,and values of RSD′s (n=6) found were less than 7.0%.