Verification of a standard method based on immunoaffinity column cleanup and HPLC-FLD analysis for determination of aflatoxins in peanut kernels

Determination of aflatoxins as a group of potent contaminations in many food products is a common analysis in food quality control laboratories. For quantification of the four most toxic aflatoxins (AFs) (i,e. AF B1, B2, G1, and G2) in food and feed, a standard method involving a liquid extraction step followed by immunoaffinity purification and high-performance liquid chromatography (HPLC) is often used. In this work, this method is verified based on the requirements of ISO/IEC 17025 for the determination of aflatoxins in peanut kernel samples. All the method figures of merit including calibration, evaluation of limit of determinations (LODs) and limit of quantifications (LOQs), accuracy, precision, and uncertainty of the method are explained in detail. The accuracy of the applied method was verified by analysis of a CRM and calculation of the recovery. The relative standard deviations of the method (n = 6) were in the range of 4.99–7.85%. The LODs and LOQs of the method were found to be 0.15 and 0.50 μg. kg−1 for AFB1 and G1 and 0.06 and 0.2 μg kg−1 for AFB2 and G2, respectively. Finally, the uncertainties in the determination of aflatoxins concentrations, at the maximum permissible levels were calculated using the GUM procedure as 0.42, 0.094, 0.42, and 0.083 μg. kg−1 for AFB1, B2, G1, and G2, respectively.