Determination of aflatoxins in compound feedstuffs containing citrus pulp

A method is described for determining aflatoxins B1, B2, G1, and G2 in compound feedstuffs containing citrus pulp. A finely ground sample is extracted with methylene chloride in a blender and cleaned with lead acetate. An aliquot of the cleaned extract is partitioned into methylene chloride and evaporated to dryness. The residue is dissolved in 0.5 mL chloroform. A 10 muL sample is applied to a thin layer chromatographic (TLC) plate and developed in 2 dimensions. Aflatoxins B1, B2, G1, and G2 are resolved and quantitated visually. The average recoveries were 96, 104, 98, and 102%, respectively. As little as 5 micrograms aflatoxin B1 or G1/kg, and 1.5 micrograms aflatoxin B2 or G1/kg can be determined by this procedure.