Application of Immunoaffinity Columns to Mycotoxin Analysis

Abstract

Abstract Immunoaffinity columns (lACs) are widely used for cleanup and isolation of mycotoxins extracted from foods and biological fluids, particularly afla-toxins, ochratoxin A, and fumonisinsẳ The columns are prepared by binding antibodies specific for a given mycotoxin to a specially activated solid-phase support and packing the support suspended in aqueous buffer solution into a cartridge. The mycotoxin in the extract or fluid binds to the antibody, impurities are removed with water or aqueous solution, and then the mycotoxin is desorbed with a miscible solvent such as methanol. Further separation can be performed with lAC, followed by liquid chromatographic (LC) quantitation, either off-line or on-line in an automated system, or by fluorometryằ lACs have been used by laboratories that developed the antibodies but are also available commercially for aflatoxins, ochratoxin A, fumonis-ins, zearalenone, and deoxynivalenolễ Among commercial lACs, Aflatest P is used as the cleanup step in an LC method and in a solution fluorometry method for corn, peanuts, and peanut butter that was adopted as an AOAC INTERNATIONAL Official Method after evaluation by an international collaborative study. As part of a fluorometer-based test kit, aflatest P was further certified by the AOAC Research Institute to measure total aflatoxins in 10 grains and grain products. lACs can concentrate the analyte from a large amount of sample, allowing detection limits at low parts-per-trillion levels in some cases (e.g., for aflatoxin Mi and ochratoxin A in liquid food matrixes). Regeneration of lACs for reuse in aflatoxin, ochratoxin A, fumon-isin, and zearalenone analyses has been investigated.