determination of trace amounts of aflatoxins by dispersive solid phase microextraction using layered double hydroxide adsorbents followed by high performance liquid chromatography - fluorescence detector in food samples

The natural toxins of aflatoxins are produced by some kind of fungus. these fungi can grow on some plant foods derived from cereals or beans and lead to their contamination. the carcinogenicity of aflatoxin toxins has been confirmed by health authorities, even in small quantities. therefore, it is important to measure these compounds. in this study, dispersive solid phase microextraction was used to extract and preconcentrate aflatoxin toxins from aqueous samples. as adsorbent in solid phase microextraction method, layer double hydroxide (ldh) modified with sodium dodecyl sulfonate surfactant were used. the used adsorbent, after preparation and characterization, has been used directly to extract target compounds. final analysis was performed by liquid chromatography with fluorescence detector. factors affecting the extraction, including the type and amount of adsorbent, solvent, sample ph and ionic strength, surfactant concentration, homogenization rate and time were investigated and optimized. under optimal conditions, the method attained good precisions (relative standard deviation, rsd), enrichment factors and limits of detection (lods ≤ 0.17µgl-1), s/n=3) in compared with other methods. detection limit of 0.03, 0.08, 0.16 and 0.17 µgl-1 were obtained for aflatoxins b1, b2, g1 and g2, respectively. the reproducibility of the method was obtained based on the relative standard deviation in the range of 5 to 10%. the linear range of 0.2 to 100 µgl-1 for type b aflatoxin and 0.5 to 500µgl-1 for type g aflatoxin and. the optimized method was successfully applied to the determination of four types aflatoxins in real samples.