Sodium bicarbonate

The chemicals and solvents used for OTA extraction and for HPLC analysis were analytical grade or HPLC grade. The OTA standard used to prepare standard solutions for the validation of the applied methodology was obtained from Sigma-Aldrich Co. (St. Louis, MO, USA). Immunoaffinity columns used for samples purification (OchraTest™ WB) were purchased from Vicam® (Milford, MA, USA). PBS buffer pH 7.0 used during sample clean up procedure was prepared by dissolving sodium chloride (8.0 g), sodium phosphate dibasic (1.2 g), potassium phosphate monobasic (0.2 g), and potassium chloride (0.2 g) in purified water so as to obtain 1 litre of buffer. Water, acetonitrile, isopropyl alcohol, dichloromethane, and methanol were purchased from Mallinckrodt Baker B.V. (Deventer, The Netherlands); citric acid, phosphoric acid, sodium bicarbonate, sodium chloride, sodium phosphate dibasic, potassium phosphate monobasic, and potassium chloride were purchased from Carlo Erba Reagents (Cornaredo, MI, Italy); acetic acid and ethyl acetate were obtained from Sigma-Aldrich Co. (St Louis, MO, USA).