RAPID HIGH-PRESSURE LIQUID-CHROMATOGRAPHIC DETERMINATION OF AFLATOXIN-M1 IN MILK AND NONFAT DRY MILK

Abstract

A modification of the current revised Association of Official Analytical Chemists (AOAC) method is described for the rapid analysis of aflatoxin M1 in milk and nonfat dry milk. The method incorporates chloroform extraction and eliminates the need for column chromatography by using liquid-liquid partition for sample extract cleanup. Quantitation is carried out by using fluorescence detection combined with high pressure liquid chromatography (HPLC) of aflatoxin M1 which has been converted to aflatoxin M2a with trifluoroacetic acid. The method has a detection limit of 0.014 .mu.g/l (2 .times. signal/noise) for whole milk. For 6 samples of naturally contaminated nonfat dry and freeze-dried milk, the modified method gave an average result of 0.698 .mu.g/l; the AOAC method gave an average result of 0.386 .mu.g/l.