Extended validation of a senstive and robust method for simultaneous quantification of aflatoxins B1, B2, G1 and G2 in Brazil nuts by HPLC-FLD

A sensitive method for determination of aflatoxins B1, B2, G1 and G2 in Brazil nut has been developed and thoroughly validated observing parameters of compliance criteria recognized by the European Union. Samples were extracted with methanol, cleaned-up with immunoaffinity columns and analyzed and quantified by high-performance liquid chromatography with fluorescence detection and post-column derivatization. High linearity was obtained over a dynamic range of 0.2-7.0 mu g/kg for each aflatoxin. Recoveries varied from 90.6 to 102%, with reproducibility standard deviations lower than 9.5%. Limits of quantification were 0.18 mu g/kg for B1, G1 and G2 and 0.10 mu g/kg for B2. Expanded measurement uncertainties at 5.0 mu g/kg and 20 mu g/kg contamination levels for B1 and total aflatoxin, respectively, were +/- 0.789 mu g/kg and +/- 2.99 mu g/kg. Decision limits (CC alpha) and detection capabilities (CC beta), robustness and trueness were also evaluated. The result is a robust, sensitive and safe analytical method for surveillance and research of aflatoxins in Brazil nuts.