Detection and determination of aflatoxins using affinity chromatography

Aflatoxins B1, B2, G1 and G2 can be easily and rapidly detected in aqueous solutions using an affinity chromatography column coupled to a monoclonal antibody specific for the toxin molecules. Water: methanol extracts of food uncontaminated with aflatoxins were spiked with aflatoxins, diluted with water, and passed through the affinity matrix. The monoclonal antibody is bound to the aflatoxin, which can then be released by using a small volume of methanol. This results in both concentration and separation of the aflatoxin present in solution. As little as 5 ng of aflatoxin can be visualized in the methanol eluate if passed over a small florisil tip under ultraviolet light, while 0.5 ng can be detected in the methanol eluate if analysed by high performance liquid chromatography (HPLC). Thus, this system can be used to test for aflatoxins in contaminated samples by spot testing (> 5 ng) or as a means of HPLC clean-up for quantitative analysis at subnanogram levels. The advantages of this immunological assay in relation to other immunoassays and traditional methods are discussed.