Use of the Mycosep multifunctional cleanup column for liquid chromatographic determination of aflatoxins in agricultural products.

A liquid chromatographic (LC) technique has been developed that uses the Mycosep multifunctional cleanup (MFC) column. MFC columns provide a rapid 1-step extract purification. They are designed to retain particular groups of compounds that may create interferences in analytical methods. At the same time, MFC columns allow compounds of interest to pass through. In the method presented, test samples are extracted in a blender with acetonitrile-water (9 + 1). A portion of the extract is forced through an MFC column designed especially for analysis of numerous mycotoxins. Analytical interferences are retained, while aflatoxins pass through the column. Aflatoxins B1 and G1 are converted to their hemiacetals by heating a mixture of purified extract and water-trifluoroacetic acid-acetic acid (7 + 2 + 1) at 65 degrees C for 8.5 min. An aliquot of this mixture is analyzed by isocratic LC with acetonitrile-water mobile phase and fluorescence detection. A detection limit of less than 0.5 ng/g for aflatoxin B1 was obtained. Average recoveries greater than 95% total aflatoxins (B1, B2, G1, and G2) and coefficients of variation of less than 3% were obtained. The method was successfully applied to the following commodities: corn, almonds, pista-chios, walnuts, peanuts, Brazil nuts, milo, rice, cottonseed, corn meal, corn gluten meal, fig paste, and mixed feeds.