Use of zinc acetate in extract purification for aflatoxin assay of cottonseed products

The official Association of Official Analytical Chemists’ and American Oil Chemists’ Society’s methods for aflatoxin assay of cottonseed products utilize 20% lead acetate solution to remove gossypol, fatty acids, and traces of lipids as insoluble lead derivatives. The substitution of a 20% zinc acetate solution containing a trace of a trivalent metal chloride to precipitate zinc derivatives yields, in some cases, superior cleanup of interfering compounds of primary extracts.