According to (EN ISO 8294, 1999), calibration solutions were prepared by dilution of Conostan standard in hexane with additions of 25 g of purified sunflower oil in each of the volumetric flasks of 50 mL. Thus, the calibration curves were obtained by injecting a blank and five corresponding solutions in a concentration range (mg kg1) of 2–30 for Mn and Cu; 4–50 for As and Pb; 0.8–12 for Cd; 0.4–8 for Zn in purified sunflower oil.