Survey of aflatoxins in rice from Iran using immunoaffinity column clean-up and HPLC with fluorescence detection

A study was undertaken to determine levels of aflatoxins in rice. A total of 261 rice samples were analyzed by HPLC using a method was based on the extraction of 50 g of finely ground rice plus 5 g NaCl with 200 ml of 80% methanol. After filtration and immunoaffinity clean-up, 20 µl was injected onto the HPLC. HPLC analysis was carried out using a Genesis RP C18 column (250 × 4.6, 4 µm I.D.) and a mobile phase with a linear gradient of water/methanol/acetonitrile (6 : 2 : 2 v/v) over 16 min. Aflatoxins were determined after post-column derivatisation with iodine by fluorescence detection at excitation and emission wavelengths of 365 and 445 nm, respectively. It was found that 68.9% of the rice samples contained aflatoxin B1 at levels greater than 0.2 ng g(-1).