Rapid Aflatoxin B1 ELISA Kit

The Sigma-Aldrich Aflatoxin B₁ ELISA (Enzyme-Linked Immunosorbent Assay) kit is a solid phase direct competitive enzyme immunoassay. An aflatoxin specific antibody optimized to cross react with B₁ is coated to a polystyrene microwell. Toxins are extracted from a ground sample with 70% methanol. The extracted sample and HRP-conjugated aflatoxin B₁ are mixed and added to the antibody-coated microwell. Aflatoxin from the extracted sample and HRP-conjugated aflatoxin B₁ compete to bind with the antibody coated to the microwell. Microwell contents are decanted and non-specific reactants are removed by washing. An enzyme substrate (TMB) is added and colour (blue) develops. The intensity of the colour is directly proportional to the amount of bound conjugate and inversely proportional to the concentration of aflatoxin in the sample or standard. Therefore, as the concentration of aflatoxin in the sample or standard increases, the intensity of the blue colour will decrease. An acidic stop solution is added which changes the chromagen color from blue to yellow. The microwells are measured optically by a microplate reader with an absorbance filter of 450nm (OD₄₅₀). The optical densities of the samples are compared to the OD′s of the kit standards and an interpretative result is determined.