Methods for vanadium determination in fuel oil by GF AAS with microemulsification and acid digestion sampling

Two methods for vanadium determination in fuel oil are proposed using GF AAS. The first is based on the preparation of a microemulsion followed by direct injection into the graphite tube. The pyrolysis and atomization temperatures, 1500 and 2700 deg C, respectively, were chosen from the temperature curves. This procedure allows determination of vanadium with a detection limit of 0.10 μg g-1 and characteristic mass of 87 pg. The other method uses total acid digestion of the sample with sulfuric acid, nitric acid and hydrogen peroxide. In this procedure, the pyrolysis and atomization temperatures recommended were 1000 and 2700 deg C, respectively. Among the analytical characteristics for this method are a detection limit of 0.25 μg g-1 and a characteristic mass of 63 pg. The accuracy of both procedures was confirmed by the determination of vanadium in the certified reference material NIST SRM 1634c-trace metals in fuel oil. (author)