Rapid determination of aflatoxin B1 in Dutch feeding stuffs by high-performance liquid chromatography and post-column derivatization.
Concentrated feeding-stuff samples are extracted with chloroform. Clean-up of the extract is carried out by applying six samples in the middle of a thin-layer plate and developing it first with diethylether. After drying and cutting off a part of the plate, development is carried out in the opposite direction with a mixture of chloroform, acetone and water. The aflatoxin-containing part of the chromatogram is removed and extracted with a mixture of dichloromethane and acetone. In subsequent high-performance liquid chromatography (HPLC), the use of post-column derivatization with iodine in water results in a 50-fold increase in sensitivity, permitting determinations at the microgram/kg level. Recovery is better than 80%, and the detection limit is better than 1 microgram/kg. In the HPLC system described extracts from citrus pulp are eluted after aflatoxin B1.