ANALYTICAL-SCALE SUPERCRITICAL-FLUID EXTRACTION OF AFLATOXIN-B1 FROM FIELD-INOCULATED CORN

Analytical-scale supercritical fluid extraction (SFE) was applied for the removal of aflatoxin B1 from field-inoculated corn samples. Various pressures (2000-15 000 psig), temperatures (40-80-degrees-C), quantity of supercritical carbon dioxide (SC-CO2) (50-500 mL of liquid CO2), and organic modifiers were utilized to optimize the extraction method. The addition of an organic modifier to the SC-CO2 Was found to be essential to achieve high aflatoxin B1 recoveries. Modifier additions of 5-20% by volume of an acetonitrile/methanol (2:1) mixture or neat isopropyl alcohol were tested. Analysis of extracts was performed with high-performance liquid chromatography coupled with fluorescence detection of the trifluoroacetic acid derivative. Recoveries were maximized by increasing the CO2 pressure and organic modifier level to 10-15% (v/v). The SFE method yielded over 90% analyte recovery when compared to conventional solvent extraction procedures. Attempts to remove coextracted lipid matter by a supercritical fluid-based cleanup method are also described. The precision of the method is affected by the sample size and the homogeneity of the corn sample.