2.5. Extraction procedure for zearalenone
The extraction of ZEN from meat and egg samples was carried out following our previously developed method with some modifications. The sample (15 g) was extracted with 50 ml mixture of acetonitrileewater (45:05, v/v) with a high speed blending for 20 min. After blending, the samples were centrifuged (4000 rpm) for 10 min and 10 ml of the filtrate was diluted to 10 ml of deionized water. The diluted extract was cleaned-up through immunoaffinity column (ZearalaTest) at a flow rate of 3e4 drops/s. The column was washed twice with 5 ml of distilled water and ZEN was eluted from the column with 3 ml of methanol (HPLC grade). The eluted sample was evaporated to dryness at 70 C and the residue was reconstituted in 250 ml of mobile phase prior to the injection to HPLC. The mobile phase for the analysis of ZEN was acetonitrileewateremethanol (48:50:2 v/v/v) with a flow rate of 1.0 ml/min. The injection volume was 20 ml. The excitation and emission wavelength of fluorescence detector was set at 274 and 450 nm.