Simultaneous determination of aflatoxins and ochratoxin a in food using a fully automated immunoaffinity column clean-up and liquid chromatography- fluorescence detection

An automated HPLC method for the simultaneous detection of aflatoxins (AF) and ochratoxin A (OA) has been developed. The method uses an immunoaffinity column containing antibodies specific to both AF and OA. The samples were extracted with an acetonitrile/water mixture and diluted with phosphate buffer saline (PBS). The aqueous extracts were then transferred to an ASPEC HPLC system for automated clean-up using AflaOchra™ immunoaffinity columns. OA and AF were quantified using HPLC with fluorescence detection, with a run time of approximately 40 min. Limits of quantification were estimated as 0.2 μg/kg for OA and AFB ₁, AFB ₂, AFG ₁ and AFG ₂. Initial validation of this method gave average recoveries of 72-101% for OA and AF for a range of food products (maize cereal products and peanut butter). Within laboratory RSD _r and RSD _R for a 5.0 μg/kg spike level in maize cereals was found to be 7.6-10.1% (AF and OA) and 10.2-13.8%, respectively.