SFE extraction of aflatoxins (B-1, B-2, G(1), and G(2)) from corn and analysis by HPLC

A supercritical-fluid extraction (SFE) method has been developed that extracts aflatoxins B-1, B-2, G(1), and G(2) from spiked corn using modified supercritical carbon dioxide. Methanol is added to the SFE extraction cell containing the corn layered between Hydromatrix (a dispersing material) which helps to prevent the clogging of the frits and reduces the effect of moisture on the extraction. The corn is held in static extraction at 65 degrees C and 51.7 MPa for 15 min followed by a dynamic extraction with 20 mL of liquid carbon dioxide. The sample is depressurized and modifier re-added with a 10-min static extraction at 51.7 MPa followed by a dynamic extraction with 20 mt of liquid carbon dioxide. The SFE extract is collected in 10 mL of chloroform and further cleaned up with a Florisil Sep-Pak. The aflatoxins were analyzed by HPLC using fluorescence detection after post-column derivatization with iodine. Recoveries of the aflatoxins B-1, B-2, G(1), and G(2) over a range of 3 to 11 ng g(-1) averaged 77.3, 82.9, 75.4, and 80.3%, respectively.